Convertible form, fill and seal packaging machine and method

ABSTRACT

A convertible, vertical form, fill and seal packaging machine and method for making a variety of types and styles of bags and seals is disclosed. The machine produces durable, substantially air-tight bags at high speed and provides for the production of different size and make of bags and different amounts and types of product in the bags. The machine includes a film drive and pinch roll pair, a pair of film pull belts, and a pair of zipper drive rollers for pulling plastic film and zipper strip through the machine. The machine is convertible from one for producing reclosable edge fin seal bags to another for producing nonreclosable midline seal pillow type bags. Conversion from one to another is facilitated by having the pinch seal assembly mounted on a base plate which is releasably secured to a drawer-like device. This allows the pinch seal assembly to be pulled out of the machine, indexed 90°, and pushed back into the machine. The film pull belts are part of a self-contained pull belt unit which can be adjusted or removed from the machine, inverted and placed back into the machine. Different formers, fill tubes, and/or vertical sealing units are used to produce different types and styles of bags. The production of different size bags is facilitated by having the film drive roll, pull belts, and zipper drive rollers simultaneously driven in bag length increments by a common drive source. Also, to accommodate the production of different size bags, the machine includes a programmable control system, an optical mark sensor, and an adjustable film path length.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. provisional patentapplication Ser. No. 60/004,889 filed Oct. 6, 1995. Also, thisapplication is a continuation-in-part of U.S. patent application Ser.No. 08/410,673, filed Mar. 27, 1995, now abandoned, which is a CIP ofU.S. patent application Ser. No. 08/355,933, filed Dec. 14, 1994, nowU.S. Pat. No. 5,505,037, which is a continuation of U.S. patentapplication Ser. No. 08/153,273, filed Nov. 16, 1993, now abandoned,which is a continuation of U.S. patent application Ser. No. 07/905,903,filed Jun. 29, 1992, now abandoned. This application is also acontinuation-in-part of U.S. patent application Ser. No. 08/076,018,filed Jun. 14, 1993, now U.S. Pat. No. 5,400,565, which is acontinuation-in-part of U.S. patent application Ser. No. 07/905,903,filed Jun. 29, 1992, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus and methods for making bagsor packages, and, more particularly, concerns a multiple purposeconvertible vertical form, fill and seal machine and method for making avariety of styles or types of bags including overlap or fin seals,pillow, potatochip, nonreclosable or reclosable, product-filled bags.

Package or bag making machines generally referred to as vertical form,fill and seal machines and methods for manufacturing individual pillowtype packages with nonreclosable, midline overlap longitudinal seams orseals are described, for example, in U.S. Pat. Nos. 2,200,971 toSonneborn et al., granted May 14, 1940 (U.S. Cl. 93-3); 2,145,941 toMaxfield, granted Feb. 7, 1939 (U.S. Cl. 93-3); 2,154,521 to Maxfield,granted Apr. 18, 1939 (U.S. Cl. 93-3); 2,852,898 to Berg, granted Sep.23, 1958 (U.S. Cl. 53-182); 2,869,298 to Zwoyer, granted Jan. 20, 1959(U.S. Cl. 53-51); 2,960,808 to Pike, granted Nov. 22, 1960 (U.S. Cl.53-241); 3,055,154 to Markley, et al., granted Sep. 25, 1962 (U.S. Cl.53-182); 3,262,244 to Cutler, et al., granted Jul. 26, 1966 (U.S. Cl.53-182); 3,425,185 to Samways, et al., granted Feb. 4, 1969 (U.S. Cl.53-182); 3,466,850 to Hudson, et al., granted Sep. 16, 1969 (U.S. Cl.53-28); 3,530,642 to Leimert, granted Sep. 29, 1970 (U.S. Cl. 53-180);3,925,139 to Simmons, granted Dec. 9, 1975 (U.S. Cl. 156/358); 4,023,327to Simmons, granted May 17, 1977 (U.S. Cl. 53/51); 4,040,237 to O'Brien,granted Aug. 9, 1977 (U.S. Cl. 53/180); 4,043,098 to Putnam, Jr., etal., granted Aug. 23, 1977 (U.S. Cl. 53/180); 4,077,308 to Scully,granted Mar. 7, 1978 (U.S. Cl. 93/19); 4,117,647 to Rossi, granted Oct.3, 1978 (U.S. Cl. 53/502); 4,128,985 to Simmons, granted Dec. 12, 1978(U.S. Cl. 53/51); 4,136,505 to Putnam, Jr., et al., granted Jan. 30,1979 (U.S. Cl. 53/551); 4,171,605 to Putnam, Jr., et al., granted Oct.23, 1979 (U.S. Cl. 53/552); 4,144,693 to Ogata, granted Mar. 20, 1979(U.S. Cl. 53/433); 4,288,965 to James, granted Sep. 15, 1981 (U.S. Cl.53/451); 4,501,109 to Monsees, granted Feb. 26, 1985 (U.S. Cl. 53/451);4,532,753 to Kovacs, granted Aug. 6, 1985 (U.S. Cl. 53/451); 4,768,327to Mosher, granted Sep. 6, 1988 (U.S. Cl. 53/451); 4,965,986 to Klinkel,granted Oct. 30, 1990 (U.S. Cl. 53/551); 4,999,974 to Kovacs, et al.,granted Mar. 19, 1991 (U.S. Cl. 53/434); and 5,279,098 to Fukuda,granted Jan. 18, 1994 (U.S. Cl. 53/451). Typically, a heat sealable webmaterial is supplied from a roll and is guided to a former located atthe upper end of the machine. The former folds the flat web materialinto a vertically oriented tube surrounding a tubular filling mandrel orpipe. The edges of the folded web material overlap one another, and, asthe folded tube moves downwardly over the mandrel, the overlappedmarginal edge portions are heat sealed to one another by a cycliclyoperated longitudinal sealing mechanism. The web is thus formed into aweb tube which is advanced through the machine in package lengthincrements. As packages are formed by the machine, product is alsofilled into them by a feeder device located on top of the machine. Thefeeder device is driven in synchronism with the remainder of the machineand cyclicly discharges measured quantities or charges of product intothe upper end of the filling mandrel. A transverse or end sealingmechanism below the filling mandrel forms package end seals in the webtube by cyclicly flattening the tube and heat sealing the two layers ofthe flattened tube to one another through the use of two relativelymoving jaws which reciprocate toward and away from the web tube from thefront and back of the machine. During one closing movement of the jaws,the sealing mechanism simultaneously forms the top end seal of theleading package and the bottom end seal of the following package, and italso cuts the web material between the two seals to separate the leadingpackage from the web tube. Between successive operations of the jaws,the is web tube is advanced in package length increments by verticallyreciprocating the sealing jaws or by using intermittently operated feedbelts.

In the above-mentioned patents, the midline longitudinal overlap or finseam or seal is formed as the web material lays relatively flat againstthe product filling pipe or mandrel. Packaging machines which formlongitudinal fin seams or seals while the edges of the web materialextend outwardly from the product filling mandrel are described, forexample, in U.S. Pat. Nos. 5,255,497 to Zoromski, et al., granted Oct.26, 1993 (U.S. Cl. 53/551) and 4,691,499 to Umeda, et al., granted Sep.8, 1987 (U.S. Cl. 53/451).

Vertical form, fill and seal machines and methods for making reclosablebags from a bag forming film and a separate plastic zipper element withedge fin seals which extend outwardly from the product fill pipe aredescribed, for example, in U.S. Pat. Nos. 4,709,533 to Ausnit, grantedDec. 1, 1987 (U.S. Cl. 53/451); 4,894,975 to Ausnit, granted Jan. 23,1990 (U.S. Cl. 53/412); and 5,400,565 to Terminella, et al., grantedMar. 28, 1995 (U.S. Cl. 53/133.4). The plastic zipper element is fedbetween the film edges and the film and zipper are joined by verticallyoriented heated sealing bars. The thus formed and sealed tube is filledwith product through the fill tube and horizontal cross-seals andcross-cutters complete the individual bags. In these machines, thevertical and horizontal seals are formed by sealing members or jawswhich reciprocate toward and away from the plastic film from the rightand left sides of the device.

U.S. Pat. Nos. 4,355,494 to Tilman, granted Oct. 26, 1982 (U.S. Cl.53/416); 4,745,731 to Talbott, et al., granted May 24, 1988 (U.S. Cl.53/451); 4,829,745 to Behr, et al., granted May 16, 1989 (U.S. Cl.53/451); 4,869,048 to Boeckmann, granted Sep. 26, 1989 (U.S. Cl.53/451); and 5,054,270 to McMahon, granted Oct. 8, 1991 (U.S. Cl.53/552) describe vertical form, fill and seal machines which producereclosable, edge fin seal bags or packages from a film or web havingrespective zipper profiles integral with or attached to each edge of thefilm.

Vertical form, fill and seal machines and methods for making reclosablepillow bags with a midline overlap or fin seal and a zipper elementrunning along one side edge are described in U.S. Pat. Nos. 4,840,012 toBoeckmann, granted Jun. 20, 1989 (U.S. Cl. 53/410) and 5,127,208 toCuster, et al., granted Jul. 7, 1992 (U.S. Cl. 53/412).

Each of U.S. Pat. Nos. 4,617,683 to Christoff, granted Oct. 14, 1986(U.S. Cl. 383/63) and 4,909,017 to McMahon, et al., granted Mar. 20,1990 (U.S. Cl. 53/410) describe packaging machines for formingreclosable pillow type bags with midline fin seals and horizontal zippersegments.

Packaging machines and methods for manufacturing tetrahedral packagesare described in, for example, U.S. Pat. Nos. 2,741,079 to Rausing,granted Apr. 10, 1956 (U.S. Cl. 53-180); 3,082,586 to Schneider, et al.,granted Mar. 26, 1963 (U.S. Cl. 53-182); 3,090,175 to Berglund, grantedMay 21, 1963 (U.S. Cl. 53-28); 3,470,672 to Tuma, granted Oct. 7, 1969(U.S. Cl. 53-59); and 3,546,835 to Mobley, granted Dec. 15, 1970 (U.S.Cl. 53-28).

Attempts have been made to provide a vertical form, fill and sealmachine which produces more than one type of package. For example,packaging machines with vertically reciprocating cross-sealing jawsmounted on a 90° rotatable platform for making nonreclosable tetrahedralor pillow type packages are described in U.S. Pat. Nos. 3,320,719 toMurray, granted May 23, 1967 (U.S. Cl. 53-182); 3,320,720 to Murray,granted May 23, 1967 (U.S. Cl. 53-182); 3,320,721 to Murray, granted May23, 1967 (U.S. Cl. 53-182); and 3,332,206 to Murray, granted Jul. 25,1967 (U.S. Cl. 53-182).

U.S. Pat. No. 4,874,257 to Inagaki, granted Oct. 17, 1989 (U.S. Cl.383/63), describes a vertical form, fill and seal apparatus for makingreclosable, edge fin seal bags or reclosable, midline fin seal pillowbags. The apparatus is shown to include two different pairs ofcross-sealing jaws.

Although the above-described patents provide examples of vertical form,fill and seal apparatus and methods for forming bags or packages, thereis a need for an improved vertical form, fill and seal machine andmethod which not only forms edge fin seal, reclosable or nonreclosable,product-filled bags, but also which is convertible and adapted toproduce a variety of types of seals and bags, has a compactconstruction, is simple to convert from one type or style of bag toanother, operates at high speeds, which facilitates the production ofdifferent size bags, and/or readily accommodates the addition ofdifferent types and amounts of product.

SUMMARY OF THE INVENTION

In accordance with an exemplary embodiment of the present invention, aconvertible, highly adaptable, versatile vertical form, fill and sealmachine and method is provided which not only makes edge fin sealnonreclosable or reclosable bags, but also has a compact construction,is easily converted to produce other styles and types of durable,substantially air tight, product-filled bags at high speed and providesfor the production of different size bags and accommodates differenttypes and amounts of product in the bags.

In accordance with another exemplary embodiment of the presentinvention, a vertical form, fill and seal machine and method is providedwhich makes edge fin seal nonreclosable or reclosable product-filledbags. In accordance with yet another exemplary embodiment of the presentinvention, a vertical form, fill and seal machine and method is providedwhich makes midline overlap or fin seal pillow style nonreclosable orreclosable product-filled bags.

Generally, the convertible vertical form, fill and seal machine andmethod of the present invention produces reclosable, product-filled bagsby joining a reclosable zipper strip to the edges of a plastic,bag-forming film which is wrapped around a product fill tube. The zipperstrip is joined to the plastic film parallel to the longitudinal axis ofthe fill tube by heat sealing to form a flexible, plastic tube.Separate, product-filled bags are formed by cross-sealing, filling andsevering the flexible, plastic tube downstream of the product fill tube.

More particularly, the convertible vertical form, fill and seal machineof the present invention includes a common drive source forintermittently driving a drive and pinch roll pair, a pair of film pullbelts, and a pair of zipper strip drive rollers for pulling the plasticfilm and the zipper strip through the machine in bag length increments.In accordance with one embodiment of the present invention, theproduction of different size bags is facilitated by having the commondrive source activated by a control means which receives input from aregistration mark sensor which senses marks on the plastic film. Inaccordance with another embodiment, the production of different sizebags is facilitated by changing the path length of the plastic filmthrough the machine using an adjustable idler roller. The plastic filmdrive roll is driven at a slightly slower speed than the film pull beltsand zipper drive rollers to provide the proper film tension andaccommodate stretch of the plastic film as it passes through themachine.

Further, the convertible vertical, form, fill and seal machine andmethod of the present invention ensures for airtight seals along theedges of each reclosable, product-filled bag by having the zipper driverollers and a bag grabber mechanism stretch or tension the bag materialand a bag squeezer assembly squeeze the air out of the product-filledtube prior to severing and cross-sealing the bag material. The bagsqueezer assembly also serves to eliminate unnecessary air and tocompact the product in the filled bags to thereby reduce the size of thefinished bags, to decrease the risk of damage to the bags duringshipping, handling, and storage by reducing, if not eliminating, airpockets, and/or reducing the quantity of air in the finished bag tolessen air or frost damage to the product in the bag.

In order to accommodate high rates of bag production, for example 30-100bags per minute, the convertible vertical form, fill and seal machine ofthe present invention incorporates pressurized air cooling ventsadjacent each of the vertical and horizontal heat sealing bars to coolthe heat seals between the zipper strip and plastic film and the heatseals along the lower and upper edges of each bag.

In accordance with an exemplary embodiment, the convertible verticalform, fill and seal machine of the present invention produces edge finseal, reclosable, product-filled bags by repeatedly drawing bag lengthincrements of plastic film and zipper strip down along the fill tube,heat sealing the zipper strip to the plastic film wrapped around thefill tube to form a flexible plastic tube (bag precursor) usingvertically oriented platens which are reciprocated into and out ofcontact with the edges of the plastic film, cooling the heat sealbetween the zipper strip and the plastic film using pressurized air,flattening or crushing the zipper strip at bag length increments toensure an air tight seal is formed along the edges of the bags,stretching the plastic tube transverse to the fill tube, sealing theplastic tube transverse to the fill tube, filling the plastic tube withproduct, incrementing the plastic tube one bag length, stretching theplastic tube transverse to the longitudinal axis of the fill tube,squeezing the air out of the product-filled tube, forming anothertransverse seal in the plastic tube using reciprocating heater barswhich are brought into and out of contact with the plastic tube, coolingthe transverse seals using pressurized air, severing the plastic tube,and ejecting a product-filled, reclosable bag.

In accordance with another exemplary embodiment, the convertiblevertical form, fill and seal machine of the present invention producesedge fin seal nonreclosable, product-filled bags by repeatedly drawingbag length increments of plastic film and cap or tear strip down alongthe fill tube, heat sealing the cap strip to the plastic film wrappedaround the fill tube to form a flexible plastic tube (bag precursor)using vertically oriented platens which are reciprocated into and out ofcontact with the edges of the plastic film, cooling the heat sealbetween the cap strip and the plastic film using pressurized air,stretching the flexible plastic tube transverse to the fill tube,sealing the plastic tube transverse to the fill tube, filling theplastic tube with product, incrementing the plastic tube one bag length,stretching the plastic tube transverse to the longitudinal axis of thefill tube, squeezing the air out of the product-filled tube, forminganother transverse seal in the plastic tube using reciprocating heaterbars which are brought into and out of contact with the plastic tube,cooling the transverse seals using pressurized air, severing the plastictube, and ejecting a product-filled nonreclosable bag.

In accordance with still another exemplary embodiment, the convertiblevertical form, fill and seal machine of the present invention producesmidline overlap seal, pillow style, nonreclosable, product-filled bagsby repeatedly drawing bag length increments of plastic film down alongthe fill tube with the edges of the film overlapping one another, heatsealing the overlapping edges of the plastic film wrapped around thefill tube to form a flexible plastic tube (bag precursor) using avertically oriented platen which is reciprocated into and out of contactwith one edge of the plastic film, cooling the heat seal between theoverlapping edges of the plastic film using pressurized air, stretchingthe flexible plastic tube transverse to the fill tube, sealing theplastic tube transverse to the fill tube, filling the plastic tube withproduct, incrementing the plastic tube one bag length, stretching theplastic tube transverse to the longitudinal axis of the fill tube,forming another transverse seal in the plastic tube using reciprocatingheater bars which are brought into and out of contact with the plastictube, cooling the transverse seals using pressurized air, severing theplastic tube, and ejecting a product-filled pillow bag.

In accordance with a further exemplary embodiment, the convertiblevertical form, fill and seal machine of the present invention producesmidline fin seal, pillow style, nonreclosable, product-filled bags byrepeatedly drawing bag length increments of plastic film down along thefill tube with the edges of the plastic film abutting one another, heatsealing the abutting edges of the plastic film together to form aflexible plastic tube (bag precursor) using one or more verticallyoriented platens which are reciprocated into and out of contact with oneor both of the edges of the plastic film, cooling the heat seal betweenthe edges of the plastic film using pressurized air, stretching theflexible plastic tube transverse to the fill tube, sealing the plastictube transverse to the fill tube, filling the plastic tube with product,incrementing the plastic tube one bag length, stretching the plastictube transverse to the longitudinal axis of the fill tube, forminganother transverse seal in the plastic tube using reciprocating heaterbars which are brought into and out of contact with the plastic tube,cooling the transverse seals using pressurized air, severing the plastictube, and ejecting a product-filled pillow bag.

In accordance with still another exemplary embodiment, the convertiblevertical form, fill and seal machine of the present invention producesreclosable, product-filled pillow style bags by repeatedly drawing baglength increments of plastic film and zipper strip down along the filltube, heat sealing the edges of the plastic film to one another and heatsealing the zipper strip to the plastic film wrapped around the filltube to form a flexible plastic tube (bag precursor) using verticallyoriented platens which are reciprocated into and out of contact with theplastic film, cooling the heat seals between the edges of the plasticfilm and the zipper strip and the plastic film using pressurized air,flattening or crushing the zipper strip at bag length increments toensure an air tight seal is formed along the edges of the bags,stretching the plastic tube transverse to the fill tube, sealing theplastic tube transverse to the fill tube, filling the plastic tube withproduct, incrementing the plastic tube one bag length, stretching theplastic tube transverse to the longitudinal axis of the fill tube,forming another transverse seal in the plastic tube using reciprocatingheater bars which are brought into and out of contact with the plastictube, cooling the transverse seals using pressurized air, severing theplastic tube, and ejecting a product-filled, reclosable pillow stylebag.

In accordance with yet another exemplary embodiment, the convertiblevertical form, fill and seal machine of the present invention producesreclosable, product-filled pillow style bags by repeatedly drawing baglength increments of plastic film and zipper strip down along the filltube, heat sealing the zipper strip to the plastic film wrapped aroundthe fill tube to form a flexible plastic tube (bag precursor) usingvertically oriented platens which are reciprocated into and out ofcontact with the plastic film, cooling the heat seal between the zipperstrip and the plastic film using pressurized air, flattening or crushingthe zipper strip at bag length increments to ensure an air tight seal isformed along the edges of the bags, stretching the plastic tubetransverse to the fill tube, sealing the plastic tube transverse to thefill tube, filling the plastic tube with product, incrementing theplastic tube one bag length, stretching the plastic tube transverse tothe longitudinal axis of the fill tube, squeezing the air out of theproduct-filled tube, forming another transverse seal in the plastic tubeusing reciprocating heater bars which are brought into and out ofcontact with the plastic tube, cooling the transverse seals usingpressurized air, severing the plastic tube, and ejecting aproduct-filled, reclosable pillow style bag.

In accordance with one example, the convertible vertical form, fill andseal machine of the present invention may be converted from a machinefor making reclosable, edge fin seal, product-filled bags to a machinefor making midline overlap seal, pillow type, nonreclosable bags bychanging the bag forming film stock roll in the back of the machine,adjusting the film path length and machine controls for the new bagtype, size, product, etc., changing the former and fill tube, andindexing the pinch seal assembly 90° so that the respective clampingjaws are located in front and behind the plastic tube rather than to theright and left sides thereof. In accordance with a particular example,indexing of the pinch seal assembly is facilitated by having the entireassembly mounted on a base plate which is itself mounted on a drawermechanism which allows the pinch seal assembly to be pulled forwardlyout of the machine, lifted from the drawer, indexed 90°, set back intothe drawer and then pushed back into the machine.

The principle object of the present invention is the provision of aconvertible vertical form, fill and seal machine and method for forminga variety of styles and types of nonreclosable and reclosable, sealed,product-filled bags.

Another object of the present invention is the provision of an improvedvertical form, fill and seal machine and method for forming reclosable,sealed, product-filled bags.

Yet another object of the present invention is the provision of animproved vertical form, fill and seal machine and method for makingpillow style, sealed, product-filled bags.

Still another object of the present invention is the provision of amachine and method for forming product-filled bags which facilitate theproduction of bags of different size and which accommodates differenttypes and amounts of product.

A still further object of the present invention is the provision of animproved, vertical form, fill and seal machine and method for makingbags which provides for a high rate of bag production.

Still yet another object of the present invention is the provision of animproved bag making machine including bag squeezing means forselectively reducing the quantity of air retained in the finishedproduct-filled bags.

Other objects and further scope of the applicability of the presentinvention will become apparent from the detailed description to followtaken in conjunction with the accompanying drawings wherein like partsare designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front perspective view of the convertible verticalform, fill and seal machine of the present invention;

FIG. 2 is a horizontal section taken along line 2--2 in FIG. 1;

FIG. 3 is a horizontal section taken along line 3--3 in FIG. 1;

FIG. 4 is an enlarged, more detailed perspective view of the horizontalsealing and severing apparatus of FIG. 1;

FIG. 5 is a fragmentary rear perspective representation of the commondrive arrangement of the machine of FIG. 1;

FIG. 6 is a side view illustration of the lower portion of the filltube, the zipper drive roller and bag grabber assembly of the machine ofFIG. 1 with the zipper drive rollers and bag grabber mechanism in theirretracted position;

FIG. 7 is a side view representation similar to that of FIG. 6 exceptthat the zipper drive rollers and bag grabber mechanism are shown intheir extended plastic tube tensioning position;

FIG. 8 is a partial section view similar to FIG. 3;

FIG. 9 is a detailed front perspective view of the zipper drive rollerand bag grabber support and reciprocation assembly;

FIG. 10 is a schematic block diagram of the control system for themachine of FIG. 1;

FIG. 11 is a fragmentary side view illustration of a portion of the filltube;

FIG. 12 is a side view representation of the pull belt biasing andsupport assembly;

FIG. 13 is a front perspective view representation of the zipper stripsupply assembly;

FIG. 14 is a rear perspective view illustration of the plastic filmsupply assembly;

FIG. 15 is an enlarged perspective view of the plastic film drive andpinch roll of FIG. 14;

FIG. 16 is an enlarged perspective view of the adjustable slack rollerof FIG. 14;

FIG. 17 is an enlarged, detailed front perspective view of the bagsqueezer unit of the machine of FIG. 1;

FIG. 18 is a front elevational view of the bag squeezer unit of FIG. 17with the squeeze plates reciprocated spaced apart from each other;

FIG. 19 is a front elevational view representation similar to that ofFIG. 18 except that the bag squeezer plates are shown in their mostproximal position with the product-filled tubes squeezed therebetween;

FIG. 20 is a rear perspective view depiction of the mark sensor and filmpath length adjustment roller of the machine of FIG. 1;

FIG. 21 is an enlarged detail view of the hinged tensioning whisker ofthe machine of FIG. 1;

FIG. 22 is a front perspective view illustration of the stainless steeltubular frame and side panels of the machine of FIG. 1;

FIG. 23 is a fragmentary rear perspective representation of the pullbelts in an inverted orientation and in use with the machine having beenconverted to produce pillow bags;

FIG. 24 is a section view of the machine of FIG. 23 with the long axisof the oval fill tube extending between the film pull belts;

FIG. 25 is a perspective view of the vertical heater platen of FIG. 24used when producing a pillow type bag with a midline overlap or fin sealwhich lies up against the fill tube;

FIG. 26 is a schematic section view representation of the production ofa midline overlap seal for a pillow bag;

FIG. 27 is a schematic section view illustration of the production of amidline fin seal for a pillow bag; and,

FIG. 28 is a schematic section view illustration of the production of adifferent midline fin seal for a pillow bag.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with an exemplary embodiment of the present invention asshown in FIG. 1 of the drawings, a convertible vertical form, fill andseal machine set up for making reclosable, edge fin seal bags isgenerally designated by the reference numeral and shown to include avertically oriented, oval, product fill tube 12 having a productreceiving funnel 14 at its upper end 16 and a depending rod or whisker18 extending from a lower end 20. The fill tube 12, funnel 14, andwhisker 18 are preferably formed of stainless steel which provides foreasy cleaning and disinfection at the end of each working cycle. Thefunnel 14 is adapted to receive the lower end of a conventional conveyoror scale which deposits discrete bag quantities of product to themachine 10 at a selected interval during the formation of each bag. Aflexible boot or sleeve 21 is added to the lower end of fill tube 12 andserves as a flexible extension of the fill tube 12.

A heat sealable, continuous, bag forming plastic film 22 is pulled froma plastic film supply roll 24 and passes between a drive and pinch rollpair 26 and 28 oriented substantially horizontal and transverse to thelongitudinal or vertical axis of the fill tube 12. The plastic film 22passes under a directional idler roller 30 and is fed over a formingcollar 32 which causes the plastic film 22 to wrap around the fill tube12. Plastic film 22 passes between the oval fill tube 12 and aconcentric substantially oval guide member 34 which extends from thecollar 32 down along a length of the fill tube. Elongate and arcuatemembers 36 and 38 extend from the front of guide member 34 and serve asheat shields. Collar 32, guide member 34, and shields 36 and 38 arepreferably formed of stainless steel to be easily cleansed anddisinfected at the end of each working cycle.

As shown in FIGS. 2 and 3 of the drawings, guide member 34 and heatshields 36 and 38 do not extend across the entire face of the fill tube12 but leave a small axially extending gap 40 which allows right andleft hand edges 42 and 44 of plastic film 22 to extend therefrom. Thegap 40 is dimensioned to cooperate with a flange or divider 46 whichprojects from the front face of fill tube 12 and runs axially along itslength. The divider 46 is preferably formed of stainless steel with asilicon or other non-stick coating on its exterior surface.

With reference again to FIGS. 1 and 2 of the drawings, plastic film 22is drawn down the sides of fill tube 12 at least in part by a pair ofendless film pull belts 48 and 50 which are preferably spring-biasedagainst the plastic film 22 and sides of the fill tube 12 to provide theproper drive force against the plastic film 22. The machine 10 isdesigned to accommodate heat sealable plastic films ranging in widthfrom about six to thirty two inches and in thickness from about one toten thousandths of an inch (mils). One such plastic film is a heatsealable polyethylene, twenty eight inches wide, two to three milsthick, 7601PS Series produced by ARMIN Corp.

As illustrated in FIGS. 1 and 3 of the drawings, a heat sealable plasticzipper cap strip 52 having opposing and interlocking male and femalereclosable fastener elements 54 and 56 forming a continuous zipper, aninterconnecting web 58, and opposing right and left hand webs 60 and 62is pulled from a zipper strip supply roll 64 by the action of pull belts48 and 50 and a pair of zipper drive rollers 66 and 68. It is preferredthat the heat sealable webs 60 and 62 of zipper strip 52 be slightlythicker than the heat sealable plastic film 22. For example, if a 3.35mil thick plastic film is used, then the webs of the zipper strip shouldbe about 3.5 mils thick. A suitable zipper strip product is produced byMinigrip, Inc. of Orangeburg, N.Y.

Zipper strip 52 passes up and over a grooved, directional idler roller70 and down between a pair of grooved idler rollers 72 and 74. Idlerroller 70 is located off to one side of fill tube 12 while idler rollers72 and 74 are positioned so that zipper strip 52 passes down the frontof the fill tube 12 and along its midline. Right and left hand webs 60and 62 of zipper strip 52 are separated by the divider 46 as zipperstrip 52 passes down along the front of the fill tube 12. Reclosablefastener elements 54 and 56, interconnecting web 58, and a portion ofthe webs 60 and 62 are entrained within a guide bar 76. Guide bar 76extends down along the length of the fill tube 12 below the groovedidler rollers 72 and 74 and opposite the divider 46 to align and guidethe zipper strip 52 down along the front of the fill tube 12. Guide bar76 includes an axial slot 78 having an enlarged portion 80 whichaccommodates the male and female fastener elements 54 and 56 of zipperstrip 52. Guide bar 76 is preferably formed of a hard nylon material orother synthetic resin polymer and includes face plate 82 and right andleft hand grooved bars 84 and 86 attached to face plate 82 by, forexample, threaded fasteners. Also, it is preferred that each of thegrooved idler rollers 70, 72 and 74 be formed of a hard nylon or othersynthetic resin polymer material.

As shown in FIGS. 1-3 of the drawings, grooved idler roller pair 72 and74, guide bar 76 and zipper drive rollers 66 and 68 are all verticallyaligned on a common vertical axis parallel to the fill tube 12 andextending along its midline. In this position, the grooved idler rollers72 and 74, guide bar 76 and zipper drive rollers 66 and 68 all cooperatewith the divider 46 to feed the zipper strip 52 down along the front ofthe fill tube 12 with the webs 60 and 62 of zipper strip 52 locatedinwardly and in abutting relationship with the edges 42 and 44 of theplastic film 22.

Vertically oriented heater platens 88 and 90 are positioned on oppositesides of the guide bar 76 and have respective convex ends 92 and 94which are reciprocated into and out of contact with the outer surfacesof edges 42 and 44 of plastic film 22. The heater platens 88 and 90 sealthe edges 42 and 44 of plastic film 22 to the webs 60 and 62 of thezipper strip 52. Heat shields 36 and 38 serve to shield the remainder ofthe plastic film 22 and the fill tube 12 from the heat given off byheater platens 88 and 90. Heater platens 88 and 90 include one or moreheater elements 96 and 98 extending axially along the length of eachheater platen 88 and 90.

With reference again to FIG. 3 of the drawings and in accordance withone embodiment of the present invention, a major portion of the exteriorsurface of fill tube 12 is covered with a thin layer 115 of frictionreducing synthetic resin polymer coated fiberglass tape. The syntheticresin polymer material reduces friction between the fill tube 12 andplastic film 22 while at the same time reduces sweating or moistureaccumulation on the plastic film 22. Thus, the polymer layer 115facilitates incremental movement of the plastic film 22 by pull belts 48and 50. Although the machine 10 will operate without the polymer layer115 on fill tube 12, it is preferred to at least cover the exteriorsurface of the flat sides of fill tube 12 with a friction reducing wearstrip 117 in the area of the pull belts 48 and 50 especially when thepull belts are spring biased against the fill tube (FIG. 11). Thus, theplastic film 22 is sandwiched between the friction reducing (slick)material 115 or 117 and pull belts 48 and 50. It is preferred to use asynthetic resin polymer tape as the polymer material 115 since it iseasily replaced or patched when it becomes worn and plural layers can beadded as needed in heavy service areas such as adding a wear strip 117over top of the material 115 in the area of the pull belts 48 and 50(FIG. 11).

Friction reducing material, such as, synthetic resin polymer tape can beadded to other wear surfaces in the machine 10. For example, layers 93and 95 of synthetic resin polymer tape are added to the working surfaces92 and 94 of vertical heater platens 88 and 90.

Guide bar 76 and shields 36 and 38 are supported by spaced horizontalbrackets 104 and 106 which also serve to support pressurized airconduits or pipes 108 and 110 each having a plurality of openings 112and 114 for discharging air along the length of the vertical sealbetween the edges 42 and 44 of plastic film 22 and webs 60 and 62 ofzipper strip 52 for cooling the seal.

Located below the guide bar 76 is a zipper crushing or flattening means116 for flattening the plastic zipper at bag length increments to ensurean airtight seal along the upper and lower edges of the bag in the areaof the zipper. Zipper flattening means 116 is shown as an ultrasonicdevice, but it is contemplated that a pair of opposing heated bars whichare reciprocated into and out of contact with the zipper strip 52 mayalso be used.

Located upstream of the forming collar 32, is an optical sensor 118 forsensing registration marks on the plastic film 22. For example,registration marks such as black bars located at bag length intervalsmay be located near the center of the plastic film 22 and used not onlyto provide an indication of bag length increments, but also propercentering or registration of the plastic film 22 in the machine 10.Signals or information from the optical sensor 118 are fed to a computercontrol system 120 which provides control signals for starting andstopping a common drive source 122 which simultaneously drives theplastic film drive roll 26, endless film pull belts 48 and 50, andzipper drive rollers 66 and 68. In this manner, the plastic film 22 andzipper strip 52 are fed through the machine 10 in bag length increments.

The machine 10 is designed to accommodate the use of marked or unmarkedplastic film. When unmarked plastic film 22 (film which does not haveregistration marks printed thereon) is to be used in the machine 10, thecontrol system 120 is set up for unmarked film so that the output ofoptical sensor 118 is ignored. The common drive source 122 operates at aconstant running speed. For unmarked plastic film, control system 120provides a selected time interval drive signal to drive source 122 forfeeding a bag length increment of unmarked film and zipper strip throughthe machine 10. The time interval drive signal is based on the length ofbag to be produced set by operator input to computer control system 120.

When marked plastic film (plastic film having registration marks printedthereon) is being used, the computer control system 120 is set up torecognize and react to the output of optical sensor 118. When opticalsensor 118 senses a registration mark, control system 120 sends a stopsignal to drive source 122. The control system 120 can be programmed tosend a stop signal to drive source 122 immediately upon the sensing of aregistration mark (leading edge) or to send the stop signal a certaindistance past the sensing of the mark.

The present invention encompasses a variety of ways to accommodate theproduction of different length bags using marked plastic film 22. Inaccordance with one embodiment, the registration marks on the plasticfilm are located (printed) a set distance downstream from the trailingedge of each bag. For example, if it takes one-fifth (1/5) of a secondfor the drive source 122 to come to a complete stop after receiving astop signal from the control system 120 and this one-fifth (1/5) of asecond interval relates to three (3) inches of travel of plastic film 22through the machine, then each of the registration marks is locatedthree (3) inches ahead of the trailing edge of each bag length incrementof plastic film. When the registration marks are so located, the pathlength of plastic film 22 between the mark sensor 118 and the horizontalsevering means can be adjusted so that an integral number of bag lengthsof plastic film exists therebetween.

The plastic film path length between the sensor 118 and the horizontalsevering means can be adjusted by allowing for adjustment of thelocation of the optical sensor 118. An example of such a verticallyadjustable mark sensor is described in U.S. Pat. No. 5,400,565 issued onMar. 28, 1995, and which is hereby incorporated by reference.Alternatively, the plastic film path length between the mark sensor 118and the horizontal severing means can be adjusted as shown in FIG. 20using a fixed mark sensor located upstream of a horizontally adjustable(movable) idler roller which serves as a phaser roller to adjust thepath length of plastic film through the machine. An example of avertically movable phaser roller is described in U.S. Pat. No. 5,014,489issued on May 14, 1991, and which is hereby incorporated by reference.U.S. Pat. No. 5,014,489 discloses a vertically movable roller whichserves to adjust the path length of a film sheet through a film wrappingmachine. It is contemplated that the idler roller may be movedvertically either manually as shown in FIG. 3 of U.S. Pat. No. 5,014,489or as shown in FIGS. 16 and 20 of the drawings of the presentapplication, or by a motorized, linear actuator.

In accordance with another embodiment of the present invention,different bag lengths are accommodated while having mark sensor 118fixed in position by printing the registration marks in a location whichaccommodates for both the time it takes for the drive source and plasticfilm to stop and the fixed path length between the mark sensor and bagsevering means. This requires the registration marks to be printed in adifferent location for different sized bags and different stoppingdistances.

In accordance with common practice, each of the registration marks isprinted in the center of each bag length increment of plastic filmregardless of bag size (length). To ensure that the plastic film issevered in the correct location and to accommodate different lengthbags, either the mark sensor 118 is movable (adjustable) along the pathof the plastic film, the mark sensor is placed upstream of an adjustableidler roller and the film path length from the mark sensor to the bagsevering means is adjusted, and/or the drive signal is adjusted byoperator input to computer control system 120.

Yet another embodiment calls for the mark to be placed on each baglength increment a fixed distance upstream from the leading edge of eachbag length increment regardless of bag length.

When forming reclosable bags from plastic film having registration marksat bag length intervals, it is preferred that computer control system120 activate drive source 122 during a bag forming cycle and continuesto activate drive source 122 until computer control system 120 receivesinput from optical sensor 118 that the leading edge of a registrationmark has been sensed. Hence, control system 120 automatically adjuststhe duration of the drive pulse sent to common drive source 122 toaccommodate the production of different length bags. It is contemplatedthat computer control system 120 can provide for operator input toadjust the drive signal to drive source 122 and to override the outputof optical sensor 118.

As illustrated in FIGS. 1 and 4 of the drawings, the plastic film 22 andthe zipper strip 52 are joined together by heat sealing the edges of theplastic film to the webs of the zipper strip to form a plastic tube 124which is sealed along its lower edge by a first horizontal or transverseseal, filled with product, sealed along its upper edge by a secondhorizontal or transverse seal, and severed from the upstream portion oftube 124 to form a separate, product-filled, reclosable bag 126. Thiscross-sealing and severing of plastic tube 124 is accomplished by apinch seal assembly 130 located downstream of the zipper drive rollers66 and 68 and whisker 18. Pinch seal assembly 130 includes a pair ofopposing clamping jaws 132 and 134 which are reciprocated in asubstantially horizontal plane into and out of contact with the tube124. Jaws 132 and 134 support respective angled product stagers 136 and138, each having padded upper surfaces 140 and 142.

Supported for reciprocation relative to the jaws 132 and 134 areC-shaped heater elements 144 and 146 each having respective upper andlower heating surfaces 148 and 150 and 152 and 154 for forming first andsecond horizontal seals 158 and 160 across the tube 124. A knife orcutting blade 156 is located within the opening in either heater element144 or 146 and is reciprocated in order to sever the tube 124 along aline 157 midway between the first and second horizontal seals 158 and160 (FIG. 7). In accordance with one embodiment of the presentinvention, the plastic tube 124 is severed by blade 156 during initialformation of the horizontal seals 158 and 160 because the severingoccurs more quickly and cleanly when the plastic tube 124 is cold.

As will be described in greater detail below, pinch seal assembly 130 ismounted on a rectangular base plate 1000, which is itself mounted on arectangular drawer bottom 1002. Base plate 1000 and drawer bottom 1002each have a central rectangular opening 1004 and 1005 which provides forpassage of the bag precursor 124, product and bags 126 therethrough.Base plate 1000 is releasably attached to drawer bottom 1002 by fourthreaded fasteners 1006 (one near each corner of the base plate)received in respective threaded openings in drawer bottom 1002. Thedrawer bottom 1002 is attached to respective right and left drawerslides or guides 1008 and 1010 which allow the entire pinch sealassembly 130, base plate 1000, and drawer bottom 1002 to be pulledforwardly out of the machine for servicing, maintenance, adjustment orfor converting the machine to produce pillow type bags. Each drawerguide 1008 and 1010 includes an I channel 1012 and 1013, which slides ina U channel 1014, which slides in a C channel 1016 and 1018. A frontdrawer panel 1020 is attached to the drawer bottom 1002 by a pluralityof threaded fasteners 1022 received in respective threaded openings 1023in the front surface of drawer bottom 1002.

With reference to FIGS. 1, 6, 7, and 9 of the drawings, downstream ofthe pinch seal assembly 130 is a bag grabber mechanism 162 includingopposing identical pneumatic actuators 163 and 164 each havingrespective piston rods with resilient rubber end caps 166 and 168mounted on the end of each piston rod. The end caps 166 and 168 areforced against opposing sides of zipper cap strip 52 and thereby grab orclamp one corner of the bag 126 during the final stages of bag formationand tension the tube 124 as will be described in greater detail below.Bag grabber 162 is designed to cooperate with an adjacent rollerconveyor (not shown) which feeds finished, product-filled, reclosablebags to an automatic case packer or other similar packing or packagingapparatus.

Typically, the completed product-filled reclosable bag 126 has sideedges 170 and 171, a reclosable, sealed top edge 172, and a base edge174. Usually, the reclosable zipper is located along the top of afinished product-filled bag. However, certain products are now beingmarketed with a reclosable zipper along the side or bottom of the bag.Thus, it is to be understood that the finished bag could have thereclosable zipper along any edge by orienting the package design,printing, label, etc., in the desired orientation on the plastic film22.

In accordance with one example of the present invention, the fill tube12 is an oval cross section five inches wide and eight inches long andhas a vertical length of thirty-six inches. This fill tube is used witha twenty-four inch wide, two to three mil thick polyethylene film toproduce product-filled bags 126 having a top 172 to bottom 174 dimensionof about twelve inches and a width (edge 170 to edge 171) in the rangeof from about four to nineteen inches.

It is contemplated that the vertical form, fill and seal machine 10 ofthe present invention can produce edge fin seal bags having a top 172 tobottom 174 dimension of from about four to sixteen inches determined bythe size and shape of the fill tube and width of the plastic film. Theamount of product added to each bag may range from about zero to tenpounds. The machine 10 can produce product-filled reclosable bags athigh rates of from thirty to one hundred or more bags per minutedepending on the size of bag being produced. At a bag production rate ofthirty bags per minute, each bag forming sequence is about two secondswhich requires the different components of the machine 10 to operatevery rapidly. At thirty bags per minute, the machine 10 can produce1,800 bags an hour and 14,400 bags in an eight hour shift if the machinewere operated continuously.

With reference to FIGS. 1 and 17-19 of the drawings, and in accordancewith one embodiment of the present invention, downstream of the pinchseal assembly 130 and bag grabber mechanism 162 and below base plate1000 and drawer bottom plate 1002 is a bag squeezer unit 950 includingopposing squeeze plates 952 and 954 each having respective squeeze pads956 and 958 attached to the inner surface thereof. The pads 956 and 958are forced against opposing sides of the product-filled tube 124following tensioning of the tube (stretching) by zipper drive rollers 66and 68 and bag grabber mechanism 162 and prior to horizontal sealing andsevering of the tube by pinch seal assembly 130 in the final stages ofbag formation. The bag squeezer unit 950 removes excess air and/orcompacts the product in the product-filled tube 124 prior to sealing andcompletion of the reclosable bag 126. Removal of the excess air andcompaction of the product serves to enhance the aesthetic appearance ofthe finished bags, and reduces the size of the finished bags therebyallowing for a greater number of bags to be packed into a case and/orallowing the case size to be reduced facilitating the shipment andstorage of more cases per pallet, truck, train, etc. Reducing the sizeof the bags also reduces shelf space or storage requirements by retailoutlets and consumers. Also, by removing excess air from the bags, thebag squeezer unit 950 reduces freezer burn or frost damage to frozenpackaged products and reduces damage to the bags and products duringshipping, handling and storage by reducing or eliminating air pocketsand shifting of the products in the bags.

In accordance with the present invention, an exemplary bag formingsequence is started by retracting the squeeze pads 956 and 958 of bagsqueezer 950 and the bag grabber end caps 166 and 168 of pneumaticactuators 163 and 164 to release a previously formed product-filledreclosable bag 126. Next, a bag length increment of plastic film 22 andzipper strip 52 is drawn down through the machine 10 by activatingcommon drive source 122 and thereby rotating drive roll 26, film pullbelts 48 and 50, and zipper drive rollers 66 and 68 in anaccelerate-run-decelerate cycle increment. When the bag length incrementof plastic film and zipper strip is being pulled down through themachine 10, the zipper drive rollers 66 and 68 are in their retractedposition (FIG. 6) where they are aligned vertically with the guide bar76 and grooved idler rollers 72 and 74 along a vertical axis parallel tothe longitudinal axis of the fill tube 12.

Next, heater platens 88 and 90 are reciprocated inwardly toward thedivider 46 so that heating surfaces 92 and 94 are brought into contactwith edges 42 and 44 of the plastic film 22 in order to produce a heatseal between the webs 60 and 62 of zipper strip 52 and the plastic film22. Zipper flattening means 116 is brought into contact with the zipperportion of the zipper strip 52 in order to flatten the zipper in thearea where the tube 124 is to receive horizontal seals and be severed.

Prior to clamping jaws 132 and 134 against tube 124, the bag grabber endcaps 166 and 168 are clamped against the zipper strip 52 of plastic tube124 and then zipper drive rollers 66 and 68 and bag grabber end caps 166and 168 are extended away from fill tube 12 to stretch the plastic tube124 opposite a lower flattened end 180 of the whisker 18 (FIG. 7).Zipper drive rollers 66 and 68 and end caps 166 and 168 are kept intheir extended bag tensioning or stretching position until the end ofthe bag-forming cycle so that the tube 124 is stretched at its baseduring filling with product, severing, and the formation of thehorizontal seals. Stretching of the tube 124 prior to severing andsealing helps to ensure a clean sever and that airtight horizontal sealsare formed by eliminating wrinkles from that area of the tube 124. Also,the bag grabber end caps 166 and 168 and/or bag squeezer squeeze pads956 and 958 support the previously filled and sealed tube portion tofurther reduce wrinkling in the area of the tube 124 to be horizontallysealed and severed.

While the tube 124 is being stretched by the zipper drive rollers andbag grabber, squeeze plates 952 and 954 or pads 956 and 958 of bagsqueezer 950 are brought together to squeeze the excess air from theproduct-filled plastic tube. Next, clamping jaws 132 and 134 are broughttogether so that tube 124 is clamped therebetween and stagers 136 and138 are brought into proximity with tube 124 and allow product to bedropped down through funnel 14 and fill tube 12 into the area of thetube 124 above the stagers 136 and 138. Surfaces 140 and 142 of thestagers are padded to cushion the impact of the product against the tube124.

The C-shaped heater bars 144 and 146 are brought into contact with thetube 124 to form the first and second horizontal seals 158 and 160. Thecutting blade or knife 156 is reciprocated to slice through the tube124. As heater platens 88 and 90 are pulled away from the zipper strip52 and plastic film edges 42 and 44, and heater bars 144 and 146 arereciprocated away from the plastic tube 124, the vertical seals andcross-seals (horizontal seals) are cooled with pressurized air.

It is to be understood that FIG. 1 of the drawings is somewhat schematicfor the sake of clarity. For example, a portion of the plastic tube 124has been removed in the area of the base 20 of the fill tube 12 and thedepending whisker 18. Also, knife blade 156 is shown separate from thejaws 132 and 134 when, in fact as shown in FIG. 4 of the drawings, knifeblade 156 is supported within the heater bar 144 of jaw 132. Further, atthe end of a bag forming cycle and the beginning of the next cycle, thejaws 132 and 134 would be clamped against the tube 124 and the tube 124would be filled with a bag increment of product in the area of stagers136 and 138.

With reference again to FIG. 2 of the drawings, the machine 10 is shownwithout the plastic film 22 or zipper strip 52 loaded therein. It is asimple matter to load and unload the plastic film and zipper strip toand from the machine 10. For example, at the end of the work day whenthe machine is to be cleansed and disinfected, one need only cut theplastic film 22 upstream of the drive roll 26 and cut the plastic zipperstrip 52 between the grooved rollers 70 and 72, and thereafter drive thefilm pull belts 48 and 50 and zipper drive rollers 66 and 68 asufficient length of time to pull the entire remaining pieces of plasticfilm 22 and zipper strip 52 through the machine 10. Next, endless filmpull belts 48 and 50 are reciprocated away from fill tube 12 and heaterplatens 88 and 90 are reciprocated away from divider 46 a sufficientdistance to allow them to pass by guide bar 76 and be moved away fromfill tube 12. Then, fill tube 12, guide member 34, collar 32, heatshields 36 and 38, air conduits 108 and 110, guide bar 76 and horizontalbrackets 104 and 106 are moved forward on slides or guides away from theother machine components a sufficient distance to be cleansed andsanitized using conventional high pressure hot water cleaning equipment.

Loading of the plastic film 22 and the zipper strip 52 in the machinemerely requires feeding the end of the plastic film 22 between the driveand pinch rolls 26 and 28, under directional roller 30, over collar 32and down between guide member 34 and fill tube 12 and feeding zipperstrip 52 over grooved roller 70, down between grooved rollers 72 and 74,down over divider 46, and into guide bar 76. Pulsing of the common drivesource 122 causes drive roll 26 and endless film pull belts 48 and 50 tomove the plastic film 22 and zipper strip down along fill tube 12 andthrough guide bar 76. Although it is not shown in FIG. 1, it is to beunderstood that a short zipper strip guide element 182 having the samecross-section as guide bar 76 can be added just above zipper driverollers 66 and 68 to ensure that zipper strip 52 is fed to and remainsin the correct position between the rollers 66 and 68 (FIGS. 6 and 7).Once the plastic film 22 and zipper strip 52 have been fed down betweenclamping jaws 132 and 134, the machine 10 is ready to produceproduct-filled reclosable bags.

With reference to FIG. 8 of the drawings and in accordance with adifferent embodiment of the present invention, the zipper strip 52 isreplaced with a different zipper strip 186 having interlocking male andfemale fastener elements 188 and 190, each attached to a central area ofrespective plastic webs 192 and 194 with webs 192 and 194 beingultrasonically joined or heat sealed together at their outer edge 196.The inner edges of the webs 192 and 194 are joined to the outer edges 42and 44 of plastic film 22 in the same fashion as the webs 60 and 62 ofzipper strip 52.

With reference again to FIGS. 1 and 4 of the drawings, and in accordancewith an exemplary embodiment of the present invention, the pinch sealassembly 130 is shown to include a rotary actuator 200 which is operatedunder computer control by computer control system 120. As illustrated,the rotary actuator 200 may comprise a Schrader Bellows PTR252 orNUMATICS dual rack and pinion rotary actuator or a two inch bore doublerack pneumatic rotary actuator sold under the trademark "BIMBA PNEUTURN"by BIMBA Mfg. Corp. The rotary actuator 200 provides approximately 180°of clockwise or counterclockwise rotation with up to several hundredinch pounds of torque. Various other forms of rotary actuators includingpneumatic, hydraulic, or electric motor actuators and other cylinderactuators are available and may alternatively be utilized for the rotaryactuator 200. It will be noted, however, that the double rack mechanismhas the advantage that the linear forces involved tend to balance due tothe oppositely directed linear motion of the two racks. The rotaryactuator 200 is provided with a flexible air hose 201 connected to anair pressure source via solenoid valves responsive to electronic signalsfrom the computer control system 120, and possibly air flow controlvalves for controlling speed and acceleration of the mechanism. Thepinch sealer drive mechanism of the present invention is similar to thatshown in U.S. Pat. No. 5,167,107 issued on Dec. 1, 1992.

The rotary actuator 200 is secured in a fixed position on the jaw baseplate 1000 and has an output shaft 202 on which is mounted a disc 204serving as a two lever crank and also as a belt sprocket. The crankfunction of disc 204 is implemented by pins 206 and 208 serving aspivots for links 210 and 212. Each of the links 210 and 212 has anoffset or dogleg to permit rotation of disc 204 through 180° withoutinterference between links 210 and 212.

Two slide rods 214 and 216, which are fixed to the base plate 1000 byupstanding brackets 217, serve as a track for the reciprocating motionsof pinch seal sliders 218 and 220. Low friction bushings or bearings 222serve to reduce the sliding friction of sliders 218 and 220 on rods 214and 216. Sliders 218 and 220 are provided with pins 224 and 226 servingas pivot pins to connect one end of slider 218 to link 210 and one endof slider 220 to link 212. As shown in FIG. 4 of the drawings, sliders218 and 220 are in their most distant position and will be drawntogether by clockwise motion of disc 204 and will reach their mostproximate position after about 180° rotation of disc 204.

An endless toothed belt 228 provides a driving connection between disc204 and a sprocket 230 mounted on a rotatable shaft 232. Shaft 232 isbeyond the range of travel of slider 220 and extends to and beyond theopposite end of slider 220 where a sprocket 234 is secured thereon.Rotation of disc 204 is transmitted by belt 228, sprocket 230, shaft232, sprocket 234, and through a belt 236 to a disc 238 which isrotatably mounted on a shaft coaxial with the output shaft 202 of rotaryactuator 200 and supported in a bushing or bearing in the rear surfaceof a support block 240 fixed to base plate 1000. Pins in disc 238pivotally connect disc 238 to links 246 and 248. Links 246 and 248 arepivotally connected at their extreme ends by pins 242 and 244 to thesliders 218 and 220. Belt tensioning assemblies 250 and 252, eachincluding grooved idler rollers 251 and 253, are provided for tensioningthe belts 236 and 228.

Thus, it will be seen that there is provided a link and slider mechanismoperated by disc 238 which is an exact counterpart of the mechanismoperated by disc 204, and that disc 238 operates in unison with disc 204thereby causing the motion of the one end of sliders 218 and 220 toconform to the motion of the other end thereof. It is contemplated thatrotary actuator 200 could be operatively attached to either end of shaft232 or to the shaft supported by block 240 in place of being attached toshaft 202 and still provide the necessary rotary actuation to the pinchseal assembly 130.

In accordance with the particular embodiment shown in FIG. 4 of thedrawings, the clamping jaw 132 of pinch seal assembly 130 is made up ofthe slider or slider bar 218 and upper and lower parallel plates 258 and260 projecting inwardly toward the center of the assembly from the innersurface of slider 218 (FIG. 1). Likewise, jaw 134 is made up of theslider 220 and upper and lower parallel plates 262 and 264 projectingfrom the inner surface of the slider 220. Stagers 136 and 138 aremounted on the upper surface of the plates 258 and 262 respectively.Heater bar 144 is mounted for reciprocation relative to jaw 132 by beingsupported on piston rods 266 of air cylinder units 268 and 270. Aircylinder units 268 and 270 are mounted on the exterior surface of theslider 218 with each cylinder rod 266 passing through the slider 218 andbeing connected to the rear surface of the heater bar 144. Similarly,the heater bar 146 is mounted for reciprocation relative to jaw 134 bybeing attached to respective cylinder rods 272 of air cylinder units 274and 276. The air cylinder units 274 and 276 are mounted on the exteriorsurface of the slider 220 with each cylinder rod 272 passing throughslider 220 and being connected to the rear surface of the heater bar146.

Activation of the air cylinder units 268, 270, 274, and 276 causesextension of their respective cylinder rods and, as such, forces thefront surfaces 148 and 150 of the heater bar 144 to extend beyond thefront surface of the jaw 132 and likewise causes the front surfaces 152and 154 of the heater bar 146 to extend beyond the front surface of jaw134. Deactivation of air cylinder units 268, 270, 274 and 276 causesretraction of their respective cylinder rods and, hence, retraction ofthe heater bars 144 and 146 back into clamping jaws 132 and 134. Each ofthe air cylinder units 268, 270, 274, and 276 is provided with aflexible air hose connected with a source of pressurized or compressedair via solenoid valves responsive to electronic signals from controlsystem 120.

Each of the upper and lower plates 258 and 260 of clamping jaw 132 and262 and 264 of clamping jaw 134 includes a plurality of small airpassages 278 for supplying pressurized air in the area of the heaterbars 144 and 146 to cool the cross-seals 158 and 160 formed in theplastic tube 124. In accordance with the particular embodiment shown,each of the plates 258, 260, 262 and 264 includes one elongate airpassage extending along the length of the plate and set back a shortdistance from the front surface of each plate (passage 280 in plate 258and passage 282 in plate 262), a groove running along the length of eachplate parallel to the elongate air passage (groove 284 in plate 258,groove 286 in plate 262, and groove 288 in plate 260), and a pluralityof cross passages which provide fluid connection between the elongateair passage (284 and 286) extending along the length of each plate andthe groove in each plate (air passages 278 in groove 288 of plate 260).A source of pressurized air is connected via flexible conduits and asolenoid valve to each of the elongate air passages in each of theplates 258, 260, 262, and 264.

With reference again to FIG. 4 of the drawings, knife blade 156 ismounted for reciprocation relative to heater bar 144 and clamping jaw132 via a pair of air cylinder units 292 and 294, each having arespective piston rod or shaft 296 and 298 connected to opposite ends ofthe knife blade 156. The air cylinder units 292 and 294 are mounted onthe outer surface of the slider 218 and have their respective shafts 296and 298 passing through the slider 218. Although knife blade 156 isshown mounted within the central cutout or groove of heater bar 144, itis contemplated that the knife blade 156 could be mounted forreciprocation with respect to either heater bar 144 or 146. Activationof the air cylinder units 292 and 294 causes extension of the shafts 296and 298 which forces knife blade 156 to extend beyond the front boundaryof heater bar 144 and slice through the plastic tube 124 between thelocation of the upper and lower horizontal seals 158 and 160.Deactivation of the air cylinder units 292 and 294 causes retraction ofthe shafts 296 and 298, which pull the knife blade 156 back within theconfines of the heater bar 144. A source of pressurized air is connectedvia flexible conduits and solenoid valves to each of the air cylinderunits 292 and 294. The solenoid valves are operated under control of thecomputer control system 120 to provide for extension and retraction ofthe respective shafts. Suitable air cylinder units are produced by BIMBAMfg. Corp.

The stagers 136 and 138 serve to support the product dropped downthrough funnel 14, fill tube 12, and into the plastic tube 124 prior toreciprocation of the clamping jaws 132 and 134 away from the tube 124.The padded surfaces 140 and 142 of the stagers 136 and 138 cushion thedynamic force of the product as it is stopped within the plastic tube124 after falling down through fill tube 12 to prevent any damage toplastic tube 124. In accordance with a preferred embodiment of thepresent invention, the flexible boot or sleeve 21 is added to the lowerend 20 of fill tube 12 and extends down to the area between the stagers136 and 138. The sleeve 21 serves as an extension of the fill tube 12,aids padded surfaces 140 and 142 in protecting the plastic tube 124 frombeing damaged by falling product, and keeps the inner surface of theplastic tube 124 free of product, moisture and grease in the area to becross-sealed and severed. Keeping the inner surface of the plastic tube124 clean in the area to be sealed and severed facilitates theproduction of air tight seals, seals which will not pull apart, and isclean and straight severing of the plastic tube. The flexible boot 21 ispreferably formed of a heavy duty flexible plastic material, such as,polyurethane belt material and is preferably removably attached to theexterior of the fill tube 12 by, for example, a plurality of threadedfasteners, a removable or replaceable metal band (FIGS. 6, 7 and 11), oran elastic band. The flexible boot 21 can be washed and sanitized orreplaced at the end of each working cycle of the machine 10.

The pinch seal assembly 130 provides for rapid reciprocating motion ofthe sliders 218 and 220 with a mechanical linkage which produces therapid accelerations for high speed operation while at the same timehaving the linkage so balanced that undesirable vibrations are almostentirely eliminated. Furthermore, the linkage, having 180° travel of thecrank, causes smooth decelerations minimizing shock and furtherenhancing the smoothness of operation and durability of the system. Thethroughput of a form, fill and seal machine is often limited by thespeed of operation of the pinch sealer and the apparatus of the presentinvention provides capability for substantially more than one hundredoperations per minute with excellent reliability and minimal vibration.

In accordance with the exemplary embodiment of the present inventionshown in FIGS. 1, 4, 9, and 22 of the drawings, the pinch seal assembly130 and base plate 1000 form a self-contained pinch seal unit 1024 whichcan be pulled forwardly out of the machine 10 on drawer bottom 1002 andslides 1008 and 1010 for service or to index the entire pinch sealassembly 90° clockwise to produce pillow type bags. Shaft 232 of pinchseal assembly 130 is supported for rotation by upstanding brackets 1026and 1028 and friction reducing bushings or bearings 1030 (FIG. 1). Thebrackets 1026 and 1028 are fixed to base plate 1000. Attached to thecenter of shaft 232 is a large knurled disc 1032 which facilitatesmanual rotation of shaft 232 and the opening or closing of jaws 132 and134.

Each of the belt tensioning assemblies 250 and 252 is of similarconstruction and includes the idler pulley 251 and 253 mounted on oneend of a lever arm 1034 and 1036 pivoted near its center by a threadedfastener 1038 and 1040 supported in the bracket 1028 and 1026. Each ofthe pulleys 251 and 253 is biased upwardly to tension the belts 236 and228 by a vertically oriented threaded member 1042 and 1044 supported ina threaded opening in a horizontal bracket 1046 and 1048 and whichcontacts the opposite end of the lever 1034 and 1036. A spherical knob1050 and 1052 is fixed to the top of each of the members 1042 and 1044to facilitate the manual turning of the members. The tension isincreased by clockwise rotation of knobs 1050 and 1052.

The air hose or hoses 201 to the rotary actuator 200, to the airpassages 280 and 282 in the plates 258, 260, 262 and 264, and to each ofthe cylinders 268, 270, 274, 276, 292, and 294 are elongated by an extrathree or four feet or include quick disconnect couplings to allow thepinch seal assembly and base plate unit 1024 to be pulled forwardly outof the machine 10 and to is allow the pinch seal unit 1024 to be indexed90°. Likewise, an electrical connection or cable 1054 between thecontrol system 120 and the pinch seal assembly 130 is elongated orincludes a quick disconnect coupling 1055 having a knurled threaded ring1056 releasably attached to a base plug 1058 extending from the topsurface of a distribution box 1060 attached to base plate 1000.Extending from the side of box 1060 are the electrical wires 1062 forthe heater bars 144 and 146 and electrical wires 1064 for a jaw positionsensor such as a metal detecting type proximity sensor or switch. Thewires 1062 are of the necessary length to accommodate the movement ofjaws 132 and 134.

The pinch seal assembly and base plate unit 1024 is moved forwardly fromthe bag production position shown in FIG. 1 to a forward servicing orindexing position by clearing the plastic film and zipper strip from thearea of the pinch seal assembly, shutting off the power to the machinecontrol system 120, loosening two threaded fasteners 1066 holding thedrawer front 1020 to machine frame 1134 (FIG. 22), uncoupling theelectrical quick disconnect 1055 (FIG. 4) and stowing the electricalcable 1054 up and out of the way, raising a locking collar 1070 up offof a hinge 1072 in whisker 18 (FIG. 21) to allow the lower end of thewhisker to swing out of the way of the rear pinch seal assemblycomponents including the disc 204, belt 228, and actuator 200, and thensimply pulling the drawer front 1020 forwardly which pulls the baseplate 1000, drawer bottom 1002 and pinch seal assembly 130 forwardly thedesired distance. Drawer slides or guides 1008 and 1010 are selected tobe sturdy enough to hold the pinch seal assembly 130, base plate 1000,drawer bottom 1002 and drawer front 1020 cantilevered out in front ofthe machine 10.

Then, the pinch seal assembly and base plate unit 1024 can be indexed90° by simply removing the four corner bolts 1006 to free the base plate1000 from the drawer bottom 1002, lifting the pinch seal assembly andbase plate unit 1024 sufficiently to clear the drawer front 1020,rotating the unit 1024 90° clockwise, placing the unit 1024 back on thedrawer bottom 1002, and reattaching the base plate 1000 to the drawerbottom 1002 using the four bolts 1006.

The unit 1024 is placed back in an operative pillow type bag productionposition (FIG. 23) by pushing the drawer front 1020 back toward themachine until drawer front 1020 contacts the machine frame 1134,inserting the bolts 1066, reattaching the electrical cable 1054 to thebox 1060, sliding locking collar 1070 over whisker hinge 1072, andturning the power back on to the machine control system 120.

In accordance with an exemplary embodiment of the present invention andas illustrated in FIG. 5 of the drawings, the common drive source 122for driving the plastic film drive roll 26, the endless pull belts 48and 50, and the zipper strip drive rollers 66 and 68 includes anelectric servomotor 300, such as, an ELECTRO-CRAFT IQ2000 or IQ5000Positioning Drive, by Reliance Electric, Eden Prairie, Minn., controlledby computer control system 120 and having an output shaft 302 serving asan input to a right angle or T-transmission 304. The transmission 304has a first output shaft 306 which provides drive to both the pull belts48 and 50 and the zipper drive rollers 66 and 68 and a second outputshaft 308 which provides drive to the drive roll 26. When servomotor 300is activated by computer control system 120, motor output shaft 302 andtransmission output shafts 306 and 308 rotate clockwise.

The drive train for the pull belts 48 and 50 includes a drive sprocket310 mounted on shaft 306 adjacent the transmission 304 and a tootheddrive belt 312 transferring drive from the sprocket 310 to a drivesprocket 314. Drive sprocket 314 is mounted on a common rotation axiswith another drive sprocket 316 which forms part of a belt transmissionincluding idler sprockets 318, 320, 322, and 324, drive sprockets 326and 328, and a toothed drive belt 330 which has teeth on both its innerand outer surfaces. The belt transmission provides a horizontallycompact vertical drive arrangement which drives the pull belts 48 and 50at equal speed but in opposite directions. It is preferred that therotation axis of each of the drive sprockets 316, 326, and 328 and eachof the idler sprockets 318, 320, 322, and 324 is parallel to therotation axis of the transmission output shaft 306.

The drive sprocket 326 is connected to an expanding universal joint orcoupling 332 which is in turn connected to an extensible shaft 334having another expanding universal joint 336 at its opposite end.Universal joint 336 is connected to a drive pulley or roller 338 whichcontacts the interior surface of the pull belt 50. The film pull belt 50is entrained around the drive pulley 338, a large idler pulley 340, andsupported by a plurality of small idler pulleys 342. Similarly, thedrive sprocket 328 is connected to an expanding universal joint 344which is connected to one end of an extensible shaft 346 having anotherexpanding universal joint 348 at its opposite end. The universal joint348 is connected to a drive pulley or roller 350 which provides drive tothe pull belt 48 by friction engagement with the interior surface of thebelt. The pull belt 48 is entrained around the drive pulley 350, a largeidler pulley 352 and supported by a plurality of small idler pulleys354. The expanding universal joints 332, 344, 336, and 348 are used inthe drive train to the pull belts 48 and 50 to allow for spring biasingof the pull belts 48 and 50 against the plastic film 22, to accommodatethe movement of the pull belts 48 and 50 away from the fill tube 12during loading and unloading of the plastic film and during cleaning andmaintenance of the fill tube 12. Extensible shafts 334 and 346 allow anentire pull belt unit 1074 (FIG. 2) including both pull belts 48 and 50to be removed from the machine for service or to invert the pull beltassembly 1074 to, for example, convert the machine 10 of FIG. 1 from amachine for producing edge fin seal bags to a machine for producingpillow type bags using a product fill tube of increased vertical length(FIGS. 23 and 24).

The drive train for the zipper drive rollers 66 and 68 includes a drivesprocket 356 attached to one end of a shaft 358 operatively connected toshaft 306 by a disc and pin arrangement 360. The disc and pinarrangement 360 includes a first disc 1076 attached to shaft 358 andincluding spaced cylindrical openings 1078 and 1080 preferably spaced180° from one another. The openings are adapted to receive respectiveelongate pins 1082 and 1084 fixed to a second disc 1086 attached toshaft 306. The pins 1082 and 1084 not only force disc 1076 and shaft 358to rotate along with disc 1086 and shaft 306, but also allow the shaft358 to move axially away from and toward shaft 306 when the zipper driverollers 66 and 68 are extended or retracted and allow the disc 1076 tobe quickly and easily operatively attached to or separated from pins1082 and 1084 and disc 1086. Hence, the drive sprocket 356 rotates alongwith shaft 358 which rotates along with shaft 306. A toothed drive belt362 transfers drive from the drive sprocket 356 to a drive sprocket 364which is coaxial with and connected to drive gear 366 and zipper driveroller 68. The teeth of drive gear 366 intermesh with the teeth of drivegear 368 which is coaxial with and connected to zipper drive roller 66.Hence, as viewed from the rear of the machine, zipper drive roller 68 isrotated counterclockwise while zipper drive roller 66 is rotatedclockwise. The rotational axis of the sprockets 356 and 364, and gears366 and 368, and of the zipper drive rollers 66 and 68 are parallel tothe axis of the output shaft 306.

Drive is transferred from the transmission output shaft 308 to a driveshaft 370 of the plastic film drive roll 26 by a drive sprocket 372mounted on the shaft 308 and a toothed drive belt 374 entrained aroundthe drive sprocket 372 and a drive sprocket 376 mounted on the driveroll shaft 370. The rotational axis of output shaft 308 is parallel tothe rotational axis of drive roll 26 and the shaft 370. In accordancewith one embodiment of the present invention, the drive sprocket 376includes an over-running clutch 377 which provides for positive drive tothe shaft 370 and drive roll 26 when the sprocket 376 is rotatedclockwise (due to rotation of the shaft 308), but also allows the roller26 and shaft 370 to rotate clockwise when the sprocket 376 isstationary. As such, the over-running clutch 377 allows the plastic film22 to be pulled through the drive and pinch rolls 26 and 28 by a machineoperator, a movable idler roller (phaser roller), or the film pull belts48 and 50 and the zipper drive rollers 66 and 68.

Although it is preferred that toothed drive sprockets and toothed drivebelts be used in the drive trains transferring drive from the servomotor300 to the drive roll 26, film pull belts 48 and 50, and zipper driverollers 66 and 68, in order to provide positive drive and preciserelative drive ratios therebetween, it is contemplated that other drivetransferring means such as sprockets and chain belts may be used. Inaccordance with an exemplary embodiment, the drive roll 26 is formed ofmetal while the pinch roll 28 is formed of rubber, the drive pulleys 338and 350 have a crowned rubber exterior surface which provides aneffective friction drive contact with the interior surface of the filmpull belts 48 and 50, and the zipper drive rollers 66 and 68 have arubber exterior surface which provides an effective friction grip withthe zipper strip 52 squeezed therebetween.

In accordance with a preferred embodiment of the present invention, thedrive roll 26 is driven at a slightly slower speed than the film pullbelts 48 and 50 and the zipper strip drive rollers 66 and 68 toaccommodate stretch or elongation of the plastic film 22 and zipperstrip 52. The drive ratios are selected to accommodates stretching ofthe particular plastic film and zipper strip material being used. Thedrive ratios can be changed by changing the radii of the drive rollersor the number of teeth on the drive sprockets used in the differentdrive trains.

In accordance with an exemplary embodiment of the present invention andas represented in FIGS. 6, 7, and 9 of the drawings, the zipper driverollers 66 and 68 and the bag grabber 162 are extended to a tubeelongating or tensioning position (FIG. 7) prior to squeezing of theproduct-filled tube 124 below the clamping jaws by bag squeezer unit950, severing the plastic tube and formation of the cross-seals 158 and160. Zipper strip drive rollers 66 and 68 and bag grabber 162 arereturned to their retracted position (FIG. 6) vertically aligned withguide bar 76 at the start of the next bag-forming cycle.

With particular reference to FIG. 9 of the drawings, a zipper driveroller and bag grabber supporting and reciprocating assembly isgenerally designated by the reference numeral 400 and shown to include apair of upper and lower slide rods 402 and 404 mounted transverse to thefill tube 12 and fixed to the base plate 1000 by end brackets 406 and408. Hence, the assembly 400 is part of the pinch seal assembly and baseplate unit 1024. A vertical slide block 412 includes upper and lowerparallel cylindrical openings 414 and 416 for receiving slide rods 402and 404. Each of the openings 414 and 416 includes a friction-reducingbushing 418 which allows slide block 412 to move freely along slide rods402 and 404. Slide block 412 also includes another cylindrical openingextending therethrough and parallel to the openings 414 and 416 foraccommodating the shaft 358 which passes through slide block 412.Likewise, end bracket 406 includes a cylindrical opening 420 whichprovides for the passage of the shaft 358 therethrough. Cylindricalopening 420 is dimensioned larger than the shaft 358 to allow the shaftto rotate relative to the bracket 406 without obstruction.

An air cylinder unit 422 is mounted on the exterior surface of bracket406 and has a piston rod or shaft 424 extending through a cylindricalopening 426 in bracket 406 and connected at its far end to the rearsurface of slide block 412. As such, extension and retraction of theshaft 424 upon activation and deactivation of the air cylinder unit 422causes translational movement of the slide block 412 along slide rods402 and 404, thus, extension and retraction of the zipper drive rollers66 and 68 and bag grabber 162 relative to the plastic tube 124.

Zipper drive rollers 66 and 68 are mounted in a cantilever fashion bybeing supported on an elongate member 428 which is fixed to a sidesurface of the slide block 412 and extends perpendicular therefrom. Agenerally triangular upper plate 430 is connected to the upper surfaceof slide block 412 and the upper surface of cantilever member 428 toprovide support and rigidity thereto. The member 428 supports aplurality of idler rollers 432 and a drive belt tensioning sprocket 434for the drive belt 362. As mentioned above with respect to FIG. 5, drivesprocket 356 is fixed to the end of the drive shaft 358 with the shaft358 and disc 1076 moving in response to movement of slide bar 412involved in the extension and retraction of zipper drive rollers 66 and68 and bag grabber 162. Idler rollers 432 and tensioning sprocket 434ensure that drive belt 362 remains entrained about drive sprockets 356and 364. Air cylinder unit 422 is connected to a source of pressurizedair via elongate flexible conduits or a quick disconnect and a solenoidvalve which is operated under the control of electronic control system120 to activate and deactivate air cylinder unit 422 at the proper timesduring the bag-forming cycle.

In accordance with the embodiment of the present invention shown in FIG.9 of the drawings, bag grabber or clamping mechanism 162 includesopposing air cylinder units 163 and 164 each having respective pistonrods or shafts extending toward each other and supporting end caps 166and 168 thereon. Each of the opposing air cylinder units 163 and 164 ismounted on a respective cantilever member 452 and 450 which is suspendedfrom plate 454 fixed to the member 428 by plates 456. A source ofpressurized air is connected to air cylinders 163 and 164 by elongateflexible conduits 458 and 460, quick disconnects and solenoid valvescontrolled by control system 120. With reference to FIGS. 1 and 17-19 ofthe drawings, bag squeezer unit 950 is fastened to the machine 10 belowdrawer bottom 1002 with squeeze plates 952 and 954 positioned onopposite sides of the plastic tube 124 with the upper edge of thesqueeze plates 952 and 954 positioned downstream of bag grabbermechanism 162 to contact with as much of the product-filled plastic tube124 as possible. Although it is not preferred, it is contemplated thatbag grabber mechanism 162 may be removed from the machine and squeezeplates 952 and 954 can be located with the upper edge thereof justdownstream of the sealing jaws 132 and 134.

In accordance with an exemplary embodiment of the present invention asillustrated in FIG. 10 of the drawings, the vertical form, fill and sealmachine 10 includes three or more electric motors, the electricservomotor 300, a first small bi-directional electric motor 468, andanother small bi-directional electric motor 470. The motor 470 is usedto drive a linear actuator for positioning the plastic film supply roll24 along its rotational axis to center the plastic film 22 with respectto the fill tube 12 and the drive and pinch roll pair 26 and 28.Electric motors 300, 468, and 470 are controlled by computer controlsystem 120. The rest of the actuators in the machine 10 are pneumatic,that is, operated by a conventional industrial source of pressurized airwhich is controlled through nine or more solenoid valves 472-488 whichare themselves controlled by computer control system 120. The nine ormore solenoid valves 472-488 control the flow of pressurized air to therespective pneumatic (air cylinder or rotary actuator) units which areused to reciprocate the following components: heater platens 88 and 90,film pull belts 48 and 50, zipper pinch (crushing) means 116, zipperdrive rollers 66 and 68, jaw members 132 and 134, heater bars 144 and146, knife 156, bag grabber 162, and bag squeezer 950. Computer controlsystem 120 receives input via optical sensor 118, one or more positionsensors and an operator input means 490, such as a touch sensitivedisplay screen and manually operated switches, to start and stop themachine, adjust the speed, sequence, and duration of bag producingsteps, to adjust the temperature of the heater means, and to operate theelectric motors. Computer input from another source, for example, alap-top PC 492 is preferred for changes in operating parameters whichshould not be operator accessible. An auxiliary motor 492 may be addedto the machine 10, for example, to serve as a zipper roller drive meanswhen the pinch seal and base plate unit 1024 is indexed 90° from theposition shown in FIG. 1. Such a servomotor having an output shaftdriven forward by a solenoid and attached to a disc with protrudingrelatively short pins can be added to the right side of the machine inposition to have the pins cooperate with the openings 1078 and 1080 indisc 1076.

With particular reference to FIG. 11 of the drawings, an upper end 532of whisker 18 tapers toward the fill tube 12 to provide a smoothtransition for the plastic film 22.

In accordance with one embodiment of the present invention as shown inFIGS. 2 and 12 of the drawings, reciprocation of the pull belts 48 and50 toward and away from the fill tube 12 and spring biasing of the belts48 and 50 against the plastic film 22 is accomplished using a disc, linkand rotary actuator assembly 550 similar to the disc 204, links 210 and212, and rotary actuator 200 of the pinch seal assembly 130. Likewise,heater platens 88 and 90 and zipper pinch means 116 may be reciprocatedby disc, link, and rotary actuator assemblies. Although it is preferredthat disc, link and rotary actuator assemblies are used forreciprocating the jaws 132 and 134, film pull belts 48 and 50, heaterplatens 88 and 90, zipper pinch means 116 and squeeze plates 952 and954, it is contemplated that other means including air cylinders andelectric solenoids or motors may be used for reciprocating these items.

Rotary actuator assembly 550 includes a rotary actuator 551, for examplea double rack pneumatic rotary actuator, with an output shaft 552secured to the center of a first disc 553 attached to a second largerdisc 554 which serves as a two lever crank. The rotary actuator 551 isconnected to a source of pressurized air via elongate air hoses, quickdisconnect fittings, and a solenoid valve responsive to electric controlsignals from computer control system 120. The crank function of disc 554is implemented by pins 556 and 558 serving as pivots for links 560 and562. The links 560 and 562 have L-shaped ends which permit rotation ofthe disc 554 through 180° without interference between the links 560 and562.

Upper and lower slide rods 510 and 512 (FIG. 12) serve as a track forthe reciprocating motions of respective sliders or slide blocks 564 and566. Low friction bushings 568 reduce the sliding friction of thesliders 564 and 566 on the rods 510 and 512. The sliders 564 and 566 areprovided with respective pins 570 and 572 serving as pivot pins toconnect the slider 564 to the link 560 and the slider 566 to the link562.

As shown in FIG. 2 of the drawings, the sliders 564 and 566 are neartheir most proximate position (pull belts 48 and 50 biased againstplastic film 22 and fill tube 12) and will be pushed apart by clockwiserotation of disc 554 when it is desired to move pull belts 48 and 50away from fill tube 12. Pull belt 48 is supported in a cantileveredfashion from the slider 566 by a pair of leaf springs 574 and 576 and abracket member 578 which supports the shafts of end roller 352 and idlerrollers 354 and includes a bearing for a central shaft of drive roller350. Likewise, pull belt 50 is supported from slider 564 by a pair ofleaf springs 580 and 582 and a bracket member 584 which supports theshafts for idler rollers 340 and 342 and includes a bearing for acentral shaft of drive roller 338. The leaf springs 574, 576, 580 and582 provide for horizontal spring biasing of the belts 48 and 50 againstthe plastic film 22 and fill tube 12 while at the same time providing astrong and rigid vertical support for operating the belts at high speedsand rapid accelerations and decelerations. In accordance with oneexample, each of the leaf springs is made of one-thirty seconds (1/32)inch thick spring steel with height and length dimensions of about three(3) inches by seven (7) inches.

The pull belt unit 1074 includes not only the assembly 550 but also anactuator support bracket 1088, and slide rod anchoring blocks 1090 and1092. The support bracket 1088 is attached to the slide rods 510 and 512and provides a rigid support for the rotary actuator 551. The anchoringblocks 1090 and 1092 are fixed to opposite ends of the slide rods 510and 512. The pull belt unit 1074 is self-contained, removable,invertible, replaceable, and adjustable. With the fill tube 12 andassociated apparatus moved out of the way or taken out of the machine10, the entire unit 1074 can be taken out of the machine for service orinversion for converting the belts from the position shown in FIGS. 1and 5 to the position shown in FIGS. 23 and 24 of the drawings.

The anchoring blocks 1090 and 1092 are releasably secured to respectivecantilevered shafts 1094 and 1096 by a plurality of threaded fasteners1098. The cantilever shafts 1094 and 1096 are fixed to the machine 10 bybrackets 1100 and 1102 secured to side panels 704 and 702.

To increase or decrease the distance between the pull belts 48 and 50,rotary actuator 551 is activated to rotate disc 554. To adjust the frontto back position of the pull belts along the sides of the fill tube toaccommodate different sizes and types of fill tubes or to allow forobstructions, for example a side zipper strip, bolts 1098 are loosenedand anchoring blocks 1090 and 1092 are moved along shafts 1094 and 1096to the desired position and then locked into place by tightening bolts1098. The height of the pull belts 48 and 50 on the fill tube can beadjusted by moving brackets 1100 and 1102 to thereby raise or lowershafts 1094 and 1096 or the entire pull belt unit 1074 can be taken out,inverted, and put back on shafts 1094 and 1096. Quick disconnects on theair hoses to the rotary actuator 551 and bolts 1098 provide for quickremoval of the unit 1074.

In accordance with one example of the present invention, a bag-formingcycle represented as starting at 0° and ending at 359° is as follows:from 0° to 15° a previously produced, product-filled reclosable bag 126is released from the machine 10 by deactivating air cylinders 164 of baggrabber 162; starting at 20° a bag-length increment of plastic film 22and zipper strip 52 is drawn down through the machine 10 by activatingcommon drive source 122 through an accelerate-run-decelerate cycle todrive film pull down belts 48 and 50 and zipper drive rollers 66 and 68aided by film drive roll 26 to draw a bag-length increment of plasticfilm and zipper strip down along fill tube 12; from 110° to 359° the aircylinders 164 of bag grabber 162 are activated to clamp the zipper strip52 between caps 166 and 168; from 110° to 359° zipper drive rollers 66and 68 and bag grabber 162 are extended to stretch or tension plastictube 124 by activating air cylinder unit 422 and extending shaft 424thereby moving slide block 412 away from rear bracket 406 and towardfront bracket 408; from 120° to 260° heater platens 88 and 90 arereciprocated toward divider 46 so that heater surfaces 92 and 94 arebrought into contact with the edges 42 and 44 of plastic film 22 to formthe seal between the zipper strip webs 60 and 62 and the edges 42 and44; from 125° to 359° jaws 132 and 134 are reciprocated toward plastictube 124 in order to clamp the tube 124 therebetween to place thestagers 136 and 138 in position adjacent the tube 124 for the receipt ofproduct, and to position the heater members 144 and 146 and the knife156 adjacent the tube 124; from 150° to 325° bag squeezer unit 950 isactivated to squeeze the product-filled tube 124 between squeeze pads956 and 958 and thereby remove excess air and/or compact the product inthe tube prior to cross-sealing; from 180° to 220° knife blade 156 isreciprocated to slice through tube 124; from 160° to 260° the heaterbars 144 and 146 are reciprocated to have their front surfaces 148 and150 and 152 and 154 brought into contact with opposite sides of theplastic tube 124 to thereby form cross-seals 158 and 160; from 160° to240° zipper weld or flattening means 116 are brought into contact withzipper strip 52 to crush or flatten the zipper in an area of zipperstrip 52 where cross-seals 158 and 160 are to be made; starting at 260°product is dropped through fill tube 12 into plastic tube 124; from 260°to 359° pressurized air is released from openings 112 and 114 inconduits 108 and 110 to cool the heat seal formed between the zipperstrip and the plastic film; and from 300° to 359° pressurized air isreleased from the openings 290 and each of plates 258, 260, 262, and 264to cool the cross-seals 158 and 160 in the tube 124. It is to beunderstood that this is an exemplary bag-forming sequence, and that theduration and sequence of events is determined by factors such as thebag-forming materials being used, the rate of operation, and the amountand type of product added to each bag.

With reference again to FIGS. 1, 6, 7, and 11 of the drawings, theflexible boot or sleeve 21 is added to the lower end 20 of fill tube 12by a releasable or replaceable metal band or strap 600 which draws thesleeve 21 tightly against the exterior of the fill tube 12. Further, thefill tube can be modified to include a plurality of nipples or nubs 602which protrude from the fill tube 12 and help keep the band 600 and(sleeve 21) from slipping down the fill tube 12. The sleeve 21 islocated between the fill tube 12 and the whisker 18 with an upper end604 located below the pull belts 48 and 50 and a lower end 606 locatedabove the zipper drive rollers 66 and 68.

It is contemplated that flexible sleeve 21 may be extended upwardly onthe fill tube 12 to cover the entire length of the fill tube 12 allowingfor projection of divider 46 therefrom by, for example, slitting thesleeve 21 and applying retaining bands 600 above and below the divider46. The plastic sleeve 21 can serve to reduce the friction between thefill tube 12 and plastic film 22, reduce sweating (moisture build up) onthe exterior of the fill tube and on the plastic film 22, as well askeep the interior of the plastic tube 124 free of moisture productand/or grease in the area to be severed and sealed. The plastic film 22and zipper strip 52 are not shown in FIG. 11 for the sake of clarity. Itis to be understood that during bag forming operation of the machine 10,the plastic film 22 covers the whisker 18, fill tube 12, wear strip 117,flexible sleeve 21, and retaining band 600.

As shown in FIG. 13 of the drawings, and in accordance with a particularembodiment, the machine 10 includes an intermittent, controlled release,zipper strip supply assembly or festooner arrangement 610 includingfirst and second spaced vertical brackets 612 and 614 which are attachedto the left side of the machine 10 as viewed from the front of themachine. The assembly 610 supports the supply roll 64 and feeds thezipper strip 52 therefrom to the grooved idler roller 70. The supplyroll 64 and bracket member 614 are shown in hidden lines to provide aclear view of the other components of the assembly 610. Supply roll 64is rotatably supported on an idler shaft 616 which rests on and isjournaled by respective pairs of idler rollers 618 and 620 attached tothe exterior of each bracket member 612 and 614. The idler rollersextend into an annular recess 622 near each end of the shaft 616.

An adjustable collar 624 on shaft 616 is brought up against one side ofsupply roll 64 and locked in position. The collar 624 ensures that theother side of supply roll 64 is brought to bear against the innersurface of a brake disc which is fixed to shaft 616 and has projectingprongs 628 which embed in supply roll 64 so that the supply roll 64rotates with disc 626 and shaft 616. A replaceable brake pad 630 isattached to the lower surface of the free end of a lever arm 632 pivotedabout a bolt or pin 634 which is attached to bracket member 612. Brakepad 630 is brought to bear against the outer surface of disc 626 by alinkage arrangement including an elongate shaft 636 which passes throughlever 632 and has a brake release assembly 638 including a releasehandle 640 attached to its upper end and a plurality of stacked cupsprings 642, a rubber spacer 644, and a pair of lock nuts 646 on itslower end. The shaft 636 passes through an opening 648 in one end 650 ofa lever 652. A pin 654 retains the shaft 636 within the opening 648.Thus, the cup springs 642 are trapped between the end 650 of lever 652and the spacer 644 and bias the brake pad 630 against disc 626 when thelever 652 is in the position shown in FIG. 13. The lever 652 ispivotally attached to bracket member 612 by a bolt or pin 655.

The upper end of an adjustable length rod 656 is attached to an end 658of lever 652 by a bolt 659 while the lower end of rod 656 is attached toan end 660 of a first support member 662 by a bolt or pin 664. A spring666 has its lower end secured to bolt 664 and its upper end secured to abolt or pin 668 attached to bracket member 612.

A plurality of lower idler rollers 670, 672 and 674 extend between anend 676 of the first support member 662 and an end 678 of a secondsupport member 662 and an end 678 of a second support member 680. Aspacer bar 682 serves to define the space between support members 662and 680 and adds rigidity and strength to the structure. A pivot bar 684passes through each of the support members 662 and 680 and has its endsattached to bracket members 612 and 614. A stop rod 686 has its oppositeends fixed to bracket members 612 and 614 and serves to limit upwardtravel of the end 660 of support member 662 and an end 688 of supportmember 680. A pair of upper idler rollers 690 and 692 have their endsjournaled in bracket members 612 and 614.

The upper and lower idler rollers 690, 692, 670, 672 and 674 serve as afestooner or accumulator for the zipper strip 52 which is pulled fromsupply roll 64. The spring 666 applies an upward force to the end 660 ofsupport member 662 and tends to draw the ends 660 and 688 up againststop rod 686 and, thereby, tension the zipper strip 52 between the upperand lower idler rollers. Also, the weight of idler rollers 670, 672 and674, spacer bar 682 and the ends 676 and 678 of support members 662 and680 tend to cause the array of idler rollers 670, 672 and 674 to hangdownwardly and thereby force the ends 660 and 688 of support members 662and 680 up against stop bar 686. As the zipper strip 52 is driventhrough the machine 10, an upward force is applied to idler roller 674by the zipper strip 52. The upward force of the zipper strip 52 and thefeeding of the zipper strip from the idler rollers will cause upwardmovement of the idler rollers 670, 672 and 674, upward movement of theends 676 and 678 of support members 662 and 680 and downward movement ofthe ends 660 and 688. Downward movement of the end 660 of support member662 causes downward movement of rod 656 and the end 658 of lever 652.Downward movement of the end 658 causes lever 652 to pivot about pin 655and raise end 650 which in turn raises shaft 636 and raises brake pad630 from disc 626. Lifting of the brake pad 630 from disc 626 allows thesupply roll 64 to rotate and the zipper strip 52 to be pulled therefrom.

When the zipper strip 52 is no longer being drawn through the machine 10and supply roll 64 continues to rotate, the accumulator (idler rollers670, 672, 674, 690, and 692) becomes filled with zipper strip. Spring666 and the weight of the idler rollers 670, 672 and 674 returns the end660 of the support member 662 to the upper position shown in FIG. 13which causes the brake pad 630 to be lowered against disc 626 and stoprotation of supply roll 64. Thus, there is a controlled feed and propertensioning of the zipper strip 52 to the machine 10.

It is contemplated that cup springs 642 may be replaced by a coil springwhich would serve the same purpose of biasing the brake pad 630 againstthe disc 626 and cushioning the impact of the pad and disc so the brakepad 630 does not bounce on the disc 626.

In order to keep the zipper strip 52 properly entrained over groovedidler roller 70 it is preferred to add another grooved idler roller 694parallel and adjacent to idler roller 70 to trap the zipper stripbetween the rollers 694 and 70. This is especially helpful when thezipper strip 52 feeds from the face of the supply roll 64 in a back andforth motion, and as such, the zipper strip travels back and forthacross idler roller 674 as it exits the festooner or accumulator.

In accordance with the particular embodiment of the present invention asis shown in FIG. 14 of the drawings, plastic film 22 from plastic filmsupply roll 24 passes through a festooner or accumulator arrangementgenerally designated 700 on its way to the drive and pinch roll pair 26and 28. In the shown embodiment, the plastic film 22 feeds from thesupply roll 24 in the back of the machine with the machine having rightand left hand sidewalls 702 and 704 as viewed from the rear of themachine. Although the plastic film 22 is shown to be fully transparentin FIG. 14 for the sake of clarity of the other machine components, itis to be understood that machine 10 is designed to operate with plasticfilm which is transparent, has registration marks, has sequentialpackaging patterns or designs, and/or which is opaque. Usually, theplastic film 22 is transparent in the area surrounding the registrationmarks so that mark sensor 118 registers the sighting of a registrationmark when a beam emitted therefrom is broken by the leading edge of themark. However, it is contemplated that when using opaque or printedplastic film, the registration marks may be in the form of transparentor white areas which reflect the beam emitted by mark sensor 118 so thatthe sensor provides an indication of the sensing of a registration markby receiving its emitted beam instead of having the emitted beamblocked.

The festooner arrangement 700 of FIG. 14 is similar to that of thefestooner for the zipper strip 52 shown in FIG. 13. For example, thefestooner arrangement 700 includes a plurality of fixed position upperidler rollers 706, 708 and 710, and an opposing levered array of loweridler rollers 712, 714 and 716 supported by first and second supportmembers 716 and 718.

A spacer bar 722 having its ends attached to the support members 718 and720 defines the space between the members and adds rigidity to the arrayor rack of lower idler rollers. Support members 718 and 720 arepivotally attached to vertical bracket members 724 and 726 along theaxis of an idler roller 728 mounted between support members 718 and 720.An L-shaped member 730 is attached to the exterior of support member 718and is adapted to receive the threaded end of a pin or bolt 732 whichprovides for the pivotal attachment of support member 718 to verticalbracket 726. An adjustable length rod 734 passes through a block 736 andhas a brake release mechanism 738 attached to its upper end. The brakerelease mechanism includes a brake release handle 740. The block 736 ispivotally attached to member 730 by a pin 742 and a like pin whichpasses through an end of support member 718. The lower end of adjustablelength rod 734 supports a plurality of stacked cup springs 744, a rubberspacer 746, and a pair of lock nuts 748. The rod 734 passes through anopening 750 and an end 752 of a brake lever 754. The rod 734 is retainedwithin the opening 750 by a pin 756. The brake lever 754 is pivotallyattached to vertical bracket 726 by a pin or bolt 758.

A replaceable brake pad 760 is attached to the lower surface of an end762 of lever 754. The brake pad 760 rests on the outer surface of abrake disc 764 which is attached to a rotation shaft 766 which supportsplastic film supply roll 24. Pairs of idler rollers 768, 770 and 772,774 support respective ends of rotation shaft 766 and are receivedwithin respective annular recesses 776 and 778 to allow for rotation ofshaft 766 while at the same time limiting axial movement thereof. Idlerroller pairs 768, 770 and 772, 774 are attached to respective brackets726 and 724. Locking collars 780 are forced against the sides of supplyroll 24 and locked to shaft 766 so that supply roll 24 rotates withshaft 766. The distance between vertical brackets 724 and 726 is fixed,however, the position of brackets 724 and 726 relative to the machine 10(sidewalls 702 and 704) is adjustable by a linear actuator including thebi-directional motor 470. Consequently, the position of plastic film 22can be precisely centered with respect to drive roll 26 and fill tube12.

A pin 782 extends through an opening or window 784 in sidewall 704 andis attached to an end 786 of support member 718. A spring 788 has itsupper end attached to pin 782 and its lower end attached in anadjustment member 788 including a plurality of openings 790 adapted toreceive a pin 792 which extends from sidewall 704.

Downward movement of the idler rollers 712, 714 and 716 is limited by anassembly including an idler roller 794, a first vertical member 796, anarm 798, and a second vertical member 800 which is fixedly attached tosupport member 720 by a threaded fastener 802. Idler roller 794 abutsagainst the plastic film on supply roll 24 and thereby limits downwardtravel of the support members 718 and 720 as they pivot about the axisof idler roller 728. A spring 804 has one end attached in an opening inthe lower end of member 800 and its other end attached to a threadedfastener 808 which is fixed to vertical bracket 724. The spring 804tends to draw the idler roller 794 against the plastic film on thesupply roll 24.

In the position shown in FIG. 14 of the drawings, the plastic film 22 ismotionless, that is, not being drawn through the machine 10. The springs786 and 804 and the weight of idler rollers 712, 714, 716 and spacer bar722 tend to draw the idler rollers to their lower position. In thislower position, the brake pad 760 is forced against brake disc 764 andthereby prevents rotation of plastic film supply roll 24. When plasticfilm 22 is drawn through the machine 10 through the combined action ofpull belts 48 and 50, zipper drive rollers 66 and 68, and drive roll 26,the plastic film 22 provides an upward or lifting force on idler roller712 which tends to draw the idler roller 712 upwardly, and forcedownward movement of the block 736 and adjustable rod 734. Downwardmovement of the rod 734 causes downward movement of the end 752 of brakelever 754 which in turn causes upward movement of the end 762 andrelease of the brake pad 760 from the brake disc 764. When the brake pad760 is moved upwardly away from the brake disc 764, the supply roll 24is free to rotate and, as such, plastic film 22 can be drawn therefromand into the accumulator or festooner of idler rollers. When the plasticfilm ceases to be drawn through the machine 10 and the accumulator fillswith plastic film 22, the springs 786 and 804 and the weight of thelower idler rollers 712, 714 and 716 draws the forward end of thesupport members 718 and 720 downwardly which causes upward movement ofthe rearward end of support member 718, and, thereby, reapplication ofthe brake pad against the brake disc 764 and stops rotation of supplyroll 24.

The machine 10 includes a plastic film 22 detector 810 which is fixed tovertical bracket 724 by a flange 812. The detector 810 includes aplunger having a friction reducing end cap 814 made of nylon or asynthetic resin polymer and which rides against the plastic film 22 andprovides an indication that plastic film 22 is being supplied undertension from supply roll 24 and up over idler roller 728. If for somereason there is no plastic film loaded in the machine, the plastic filmtears, or the accumulator ceases to function properly and the correcttension is not applied to the plastic film 22 as it passes over idlerroller 728, the plunger of detector 810 moves forward and provides anindication along a line 816 to control system 120 that there is aproblem with the supply of plastic film. This causes the sounding of analarm and causes normal operation of the machine 10 to shut down untilthe problem with the plastic film is fixed.

The machine 10 provides for the printing of information such assequential numbering of packages or date stamping of sequential bags ina printing station located between the plastic film accumulator 700 andthe pinch and drive roll pair 26 and 28. The printing station includes aplurality of idler rollers 820, 822, 824, 826 and 828, upper and lowervertically oriented slide bars 830 and 832, a printing unit 834 having adepending printing head 836 and a pair of positioning members 838 whichare received on upper slide bar 832, and an adjustable mount 840received on lower slide bar 830 and having a resilient pad 842 on itsupper surface. The resilient pad 842 is designed to be located directlybeneath the printing head 836 so that the plastic film 22 passes betweenthe pad 842 and printing head 836 with the pad 842 serving as aresilient backing or support for the plastic film as it is being printedupon by the printing head 836. Idler rollers 820 and 822 provide for ahorizontal run of the plastic film 22 between the print head 836 andbacking pad 842. The printing unit 834 and mount 840 can be moved alongslide bars 830 and 832 so that the plastic film can be printed on in adesired location such as along the edge or in the center of the plasticfilm.

As illustrated in FIGS. 14-16 of the drawings, idler roller 824 ismounted for vertical movement with respect to idler rollers 826 and 828to adjust and correctly position the plastic film 22 within the printingstation to provide that the printed matter appear in the correctlocation relative to each bag length increment and any product labelingor package printing that appears on the plastic film 22. The path lengthof the plastic film 22 between the print head 836 and the pinch sealassembly 130 (FIG. 1) is adjusted by vertically moving idler roller 824relative to idler rollers 826 and 828.

Brake release mechanism 738 and a pinch roll release mechanism 846provide for the manual loading and unloading of the plastic film 22 inthe machine 10. For example, lifting of the brake release handle 740causes downward movement of adjustable rod 734 and downward movement ofthe end 752 of brake lever 754, thus causing upward movement of end 762and movement of brake pad 760 away from brake disc 764. Release of thebrake pad 760 from the brake disc 764 allows for free rotation ofplastic film supply roll 24 to facilitate manual loading of the plasticfilm 22 into the machine 10. The plastic film 22 is drawn from thesupply roll 24, fed over idler roller 728, over idler roller 706, downunder idler roller 716, back up over idler roller 708, down under idlerroller 714, back up over idler roller 710, down under idler roller 712,up over idler roller 820, under idler roller 822, over idler roller 826,under idler roller 824, over idler 828, under pinch roll 28, and upbetween pinch roll 28 and drive roll 26.

As much as the drive roll 26 is in a fixed position relative to themachine 10, release mechanism 846 provides for pivotal movement of thepinch roll 28 away from drive roll 26 and thereby allows feeding of theplastic film therebetween. The pinch roll 28 is an idler roller which isfree to rotate about its rotation axis, so once it is moved away fromdrive roll 26 it is a simple matter to feed the plastic film 22 underpinch roll 28 and up over drive roll 26. Once the plastic film islocated between the pinch and drive roll 28 and 26, the pinch roll isreturned to its operative position biased against drive roll 26 andfurther movement of the plastic film through the machine is facilitatedby pulsing of common drive source 122 to cause forward rotation of driveroll 26.

With reference to FIGS. 14 and 15 of the drawings and in accordance witha particular embodiment of the present invention, the pinch roll releasemechanism 846 includes first and second L-shaped members 848 and 850pivotally attached to the respective side walls 704 and 702 by threadedbolts or pins 852 and 854. The pinch roll 28 has respective end shafts856 and 858 which are attached to the L-shaped members 848 and 850 neartheir upper ends 860 and 862. The L-shaped members 848 and 850 arebiased forwardly so that the pinch roll 28 is biased against drive roll262 to squeeze the plastic film 22 therebetween by first and secondsprings 864 and 866. The spring 864 has one end attached to side wall704 by a threaded fastener 868, and its other end attached to the upperend 860 of member 848 by a threaded fastener 870. Likewise, spring 866has its forward end attached to sidewall 702 by a threaded fastener 872and its other end attached to the upper end 862 of member 850 by athreaded fastener 874.

The release mechanism 846 further includes an elongate rod 876 havingits ends journaled in side walls 702 and 704, and a circular collar 878fixed to an end 880 of rod 876 which extends through side walls 704.Attached to the collar 878 is a handle 882 which is adapted to berotated through 90° from the position shown in FIG. 15 to asubstantially horizontal position rotating the rod 876 counterclockwise.Attached to the rod 876 are two spacing blocks 884 and 886 which rotatewith rod 876 and bear against wear plates 888 and 890 which are attachedto the upper surface of the respective ends 892 and 894 of L-shapedmembers 848 and 850. In the position shown in FIG. 15 of the drawings,the blocks 884 and 886 are positioned with a short distance between therod 876 and plates 888 and 890. When the handle 882 is rotatedcounter-clockwise through 90°, a curved surface on the front end of eachof blocks 884 and 886 is brought to bear against plates 888 and 890 togradually increase the distance between the rod 876 and the plates 888and 890. The increased dimension of the blocks 884 and 886 located belowthe rod 876 forces downward movement of the ends 892 and 894 of members848 and 850 and thereby causes rearward movement of the upper ends 860and 862 of the members 848 and 850 against the bias of springs 864 and866 to cause the movement of pinch roll 28 away from drive roll 26.Clockwise movement of the handle from a horizontal position back to thevertical position shown in FIG. 15 of the drawings allows the springs864 and 866 to return the pinch roll 28 against drive roll 26 andthereby squeeze the plastic film 22 between the drive and pinch roll.The bias of springs 864 and 866 against the upper ends 860 and 862 ofmembers 848 and 850 is sufficient to keep the plates 888 and 890 againstblocks 884 and 886 and thereby tends to hold the release mechanism 846in the position shown in FIG. 15 of the drawings.

As illustrated in FIGS. 14 and 20 of the drawings, an idler roller 898has been added between idler roller 30 and forming collar 32 tofacilitate the feeding of the plastic film 22 up over forming collar 32.Optical mark sensor 118 includes light emitting and receiving sensorheads 500 and 501 and respective elongate, flexible, fiber optic cables502 and 504 which extend to a conventional light emitting and receivingunit which provides a registration mark sensed signal to control system120 when the leading edge of a registration mark on plastic film 22passes between the emitting and sensor heads 500 and 501. Mark sensor118 is located a few inches upstream of forming collar 32 with theemitting and receiving heads 500 mounted between idler roller 30 anddrive roll 26, with each head on opposite sides of plastic film 22 andcentered with respect to the center line of machine 10. Heads 500 and501 are fastened, for example, to respective movable mounting elements503 and 505 on slide bars 506 and 507 attached to side panels 704 and702 of the machine 10 which allows for repositioning of the heads 500and 501 to the edge of the film if the film is marked with edge marksrather than center marks.

As illustrated in FIGS. 14 and 20 of the drawings, idler roller 30 ismounted for horizontal movement with respect to idler roller 828 anddrive roll 26 to adjust the path length of the plastic film 22 betweenthe mark sensor 118 and the pinch seal assembly 130 (FIG. 1).

With reference to FIGS. 14 and 20 of the drawings and in accordance witha particular embodiment of the present invention, the horizontallymovable idler roller 30 includes a roller body 1104 which is mounted forrotation relative to a central shaft 1106 which extends through rollerbody 1104 and protrudes through elongate horizontal openings 1108 and1110 in brackets 1112 and 1114 attached to side walls 702 and 704 ofmachine 10. A first rack 1116 is attached to the inner surface ofbracket 1112 adjacent opening 1108 and a second rack 1118 is attached tothe inner surface of bracket 1114 adjacent opening 1110. A first pinion1120 is fixed to one end of shaft 1106 so that its teeth fit into theteeth of rack 1116 while a second pinion 1122 is fixed to the other endof shaft 1106 so that its teeth fit into the teeth of rack 1118. Handles1124 and 1126 are attached to T-brackets 1128 by threaded shafts 1130which protrude through openings 1108 and 1110 so that clockwise rotationof the handles 1124 and 1126 causes the T-brackets 1128 to squeezeagainst the side brackets 1112 and 1114 and lock the pinions 1120 and1122 in a selected position in the racks 1116 and 1118. Forward movementof the idler roller or phaser 30 with respect to feed roll 26 increasesthe path length of the plastic film 22 from mark sensor 118 to pinchseal assembly 130 (FIG. 1).

With reference to FIGS. 14 and 16 of the drawings and in accordance witha particular embodiment of the present invention, the vertically movableidler roller 824 includes a roller body 900 which is mounted forrotation relative to a central shaft 902 which extends through rollerbody 900 and protrudes through elongate vertical openings 904 and 906 inside walls 702 and 704 of machine 10. A first rack 908 is attached tothe inner surface of side wall 702 adjacent opening 904 and a secondrack 910 is attached to the inner surface of side wall 704 adjacentopening 906. A first pinion 912 is fixed to shaft 902 so that its teethfit into the teeth of rack 908 while a second pinion 914 is fixed toshaft 902 so that its teeth fit into the teeth of rack 910. A circularhandle 916 is attached to the end of shaft 902 which protrudes throughside wall 702 so that clockwise rotation of the handle 916 causesclockwise rotation of pinions 912 and 914 which causes the pinions tomove down the racks 908 and 910 to lower idler roller 824 with respectto idler rollers 826 and 828 and thereby increase the path length of theplastic film from idler roller 824 to pinch seal assembly 130 (FIG. 1).Counterclockwise rotation of handles 916 causes upward movement of idlerroller 824 and thereby shortens the path length of the plastic film 22between idler roller 824 and pinch seal assembly 130. Once the desiredlocation of idler roller 824 has been acquired, shaft 902 is locked inposition relative to sidewalls 704 and 702 by tightening threaded nutsagainst the outer surface of side walls 704 and 702.

It is to be understood that FIG. 1 is schematic and that in accordancewith at least one embodiment of the present invention the zippered capstrip and plastic film supply assemblies shown in FIGS. 13-16 of thedrawings form a part of the machine 10 shown in FIG. 1 of the drawings.Although the phaser bar or roller 824 is shown to be manually raised andlowered in FIGS. 14-16 of the drawings, it is contemplated that thevertical adjustment of the idler roller 824 can be controlled by controlsystem 120 using the electric motor 468 and a suitable drive mechanismsuch as a linear actuator.

In accordance with the exemplary embodiment of the present invention asshown in FIGS. 17-19 of the drawings, bag squeezer unit 950 includes asingle crank rotary actuator assembly 960 for reciprocating squeezeplates 952 and 954 and squeeze pads 956 and 958 toward and away from theproduct-filled tube 124 during formation of the reclosable bags 126. Thesingle crank rotary actuator assembly 960 includes a mounting plate 962which is fixed to the machine 10 and has attached thereto right and lefthand end plates 964 and 966. End plates 964 and 966 support respectiveparallel slide rods 968 and 970 which support respective slide blocks972 and 974 for purely translational movement transverse to the filltube 12 on linear bearings or bushings housed within the slide blocks.

Each of the squeeze plates 952 and 954 is removably attached to therespective slide blocks 972 and 974 for translational movement towardand away from the product-filled tube 124 by respective sections ofangle iron 976 and 978 and cantilever brackets or plates 980 and 982.The plates 980 and 982 and angle iron 976 and 978 are attached to oneanother and to the slide blocks and squeeze plates by removable threadedfasteners. This not only facilitates the removal and substitution ofvarious forms of squeeze plates or squeeze pads to the slide blocks, butalso provides for position adjustments to accommodate machinevariations, bag variations, and different types and amounts of products.

The slide blocks 972 and 974 are moved along the slide rods 968 and 970by a rotary actuator and crank arrangement including a rotary actuator984, circular cam 986, and respective cam levers or links 988 and 990.Circular cam 986 is operatively connected to a vertical output shaft 992of rotary actuator 984 by a shaft key and set screw. Crank levers 988and 990 are pivotally attached to the circular cam 986 and respectiveslide blocks 972 and 974 by threaded bolts or pins and annular bearingsmade of a conventional bearing material such as a friction reducingsynthetic resin or a soft metal such as brass.

The rotary actuator 984 is operated under computer control by thecomputer control system 120. As illustrated, the rotary actuator maycomprise a two inch bore double rack pneumatic rotary actuator soldunder the trademark "BIMBA PNEUTURN" by BIMBA Manufacturing Corp. Therotary actuator 984 provides approximately 180° of clockwise orcounterclockwise rotation of output shaft 992 with up to several hundredinch pounds of torque. Various other forms of rotary actuators includingelectric motor actuators and other air or hydraulic cylinder actuatorsare available and may be utilized for the rotary actuator 984. Thedouble rack mechanism is preferred in that the linear motions involvedtend to balance due to the oppositely directed linear motion of the tworacks. The rotary actuator 984 is provided with connection to an airpressure source via solenoid valves responsive to electronic controlsignals from the computer control system 120, and it is contemplatedthat air flow control valves for controlling speed and acceleration ofthe bag squeezer may be used.

The rotary actuator and crank assembly 960 is similar to that used inthe pinch sealer drive mechanism and other rotary actuated drivemechanisms of the machine 10. The crank levers 988 and 990 have offsetsor doglegs in each end to permit rotation of the cam 986 through 180°without interference between the levers 988 and 990. The rotary actuatorand crank assembly 960 is vertically compact, and, as such, allows thebag squeezer unit 950 to be mounted in the machine 10 with the squeezeplates 952 and 954 close to the pinch seal assembly 130.

With particular reference to FIG. 19 of the drawings, the squeeze pads956 and 958 have contoured inner bag contacting surfaces havingrespective enlargements 994 and 996 at the upper ends thereof which tendto force all air and product from the upper region of the product-filledplastic tube 124. The enlargements 994 and 996 of squeeze pads 956 and958 are spaced apart a sufficient yet small distance to allow air toescape from the upper end of the filled tube 124. The lower portions ofthe squeeze pads 956 and 958 define a bag opening which provides for theselected excess air removal and product compaction therebetween. Inaccordance with one embodiment, the squeeze pads 956 and 958 are formedof a rigid material having wear resistant exterior surface.

In accordance with another embodiment, the squeeze pads 956 and 958 areformed of a resilient material such as foam rubber having a sealed poreexterior surface. The pads 956 and 958 have curved surfaces to avoiddamaging the plastic tube 124. The squeeze plates 952 and 954 and/orsqueeze pads 956 and 958 can be replaced with alternative plates andpads depending on the type and amount of product being packaged, thesize of the bags, and the like. For example, the machine 10 may in oneinstance be used to package frozen chicken breasts, and in another,shredded lettuce or salad products. While the squeeze pads 956 and 958may work well with frozen products, just the bare squeeze plates 952 and954 (FIG. 21) may be all that is necessary to squeeze shredded saladproducts.

In accordance with an exemplary embodiment of the present invention asshown in FIG. 22 of the drawings, the machine 10 includes a stainlesssteel substructure generally designated 1132 including a tubularstainless steel frame or skeleton 1134 and a plurality of removablestainless steel panels or skins. Frame 1134 has four vertical cornermembers 1136, 1138, 1140, and 1142, six horizontal side members (threeon each side) 1144 and 1146, a horizontal front member 1148, and ahorizontal back member 1150. These tubular members or box beams arewelded together and form a sturdy, rigid frame providing a rigid stablesupport for a plurality of stainless steel panels. At the base of eachof the corner members 1136, 1138, 1140, and 1142 are respectivevertically adjustable feet 1152, 1154, 1156, and 1158 each having arubber base 1160.

Side panels 702 and 704 are attached to frame members 1136 and 1138 and1140 and 1142 by a plurality of threaded fasteners or bolts 1162 whichpass through the side panels, through circular spacers 1164, and intothe frame members. The spacers 1164 are preferably stainless steel discswhich are welded to the frame members and keep the side panels spaced adistance of one-quarter inch or more from the frame members to allow forcleaning and disinfecting therebetween. It is preferred to use stainlesssteel materials for as many of the machine components as possible sothat these materials can be cleaned and sanitized at the end of eachworking cycle, will not rust or corrode, and provide a sturdyconstruction.

The C-channels 1016 and 1018 of drawer slides or guides 1008 and 1010are attached to the front and back frame members 1148 and 1150. Drawerfront 1020 is releasably secured to frame members 1136 and 1142 bythreaded fasteners 1066 which pass through drawer front 1020, spacerelements 1164, and into the frame members. Drawer front 1020 is attachedto drawer bottom 1002 by the threaded fasteners 1022. A top panel 1166is attached to each of the side panels 702 and 704 by a plurality ofthreaded fasteners. Top panel 1166 serves as a support for the feed tubeand former. The feed tube 12 is at least partially received within aconcave recess 1168 in top panel 1166.

An upper back panel 1170 is attached to each of the frame members 1138and 1140 by a plurality of threaded fasteners which pass through theback panel 1170, through spacer members 1164 and into the frame members.Back panel 1170 includes a circular opening 1172 which provides forpassage of the drive shaft 306 therethrough. Disc 1086 is located justinside back panel 1170 with pins 1082 and 1084 protruding toward thefront of the machine. Pins 1082 and 1084 are long enough to accommodatethe extension and retraction movement of the zipper drive rollers andhave rounded forward ends which facilitate the insertion of the pinsinto the receiving openings 1078 and 1080. A lower back panel 1174 isattached to frame members 1138 and 1140 by a plurality of threadedfasteners and spacer members.

A stainless steel conduit is attached to side panel 704 and is adaptedto extend to a control box or control panel for control system 120 withthe control box being attached to side panel 704. Side panels 702 and704 also provide support for a transparent or translucent safety door(not shown) which extends between side panels 702 and 704 in the frontof the machine above drawer front 1020 to protect the machine operatorwhile the machine is in operation. A similar safety door is attached tothe back of the machine between side panels 702 and 704 and above thefilm supply roll 24. With the machine operating at high bag productionrates, for example 30-100 bags per minute, the machine componentsoperate at very high speeds and the safety doors help to prevent someonefrom inadvertently or mistakenly reaching into the machine while it isoperating.

With reference to FIGS. 23-28 of the drawings, the machine 10 has beenconverted to the production of pillow type bags rather than edge finseal bags (FIG. 1) by removing the feed tube 12, former 32, andassociated apparatus and replacing it with a fill tube 1178 having anoval cross-section with the long axis oriented right to left in themachine rather than front to back. Also, the pinch seal and base plateunit 1024 has been indexed 90° so that the sealing jaw 132 is located inthe front of the machine and sealing jaw 134 is located in the back ofthe machine rather than being on the right and left sides thereof. Inthe exemplary embodiment shown in FIGS. 23 and 24 of the drawings, thefill tube 1178 is vertically longer than the fill tube 12 and, as such,the pull belt unit 1074 has been removed from the machine, inverted andreplaced back into the machine, so that, instead of extending upwardlyfrom their respective drive shafts 346 and 334, the pull belts 48 and 50extend downwardly along the length of the fill tube 1178. The conversionof the machine 10 from a machine producing edge fin seal bags (FIG. 1)to a machine for producing pillow type bags with midline overlap or finseals is made easy by having the pull belt unit 1074 and the pinch sealand base plate unit 1024 self-contained and easily removed,repositioned, and replaced back into the machine. Also, top panel 1166of machine substructure 1132 accommodates different fill tubes andformers for producing the different types of bags in machine 10. Tofacilitate the removal of the pull belt unit 1074 from the machine,inversion, and replacement of the unit back into the machine, each ofthe extensible drive shafts 334 and 346 for the respective pull belts 50and 48 have an internal, male, hexagonal shaft segment or stub 1180 and1182 slidably received within an elongate, female, hexagonal recess inshaft segments 1184 and 1186. This arrangement of hexagonal shaft andrecess allows for elongation and contraction of the length of the driveshafts 334 and 346 and also permits the quick separation of therespective shaft elements to provide for removal of the pull belt unit1074 from the machine 10. Hexagonal shaft 1180 of drive shaft 334 hasthe exact same dimensions as the hexagonal shaft 1182 of drive shaft346. Thus, the hexagonal shaft of drive shaft 334 can be placed withinthe hexagonal recess of drive shaft 346 and are, as such,interchangeable.

For the sake of clarity, FIG. 23 is highly fragmentary and schematic andall the components of the pinch seal assembly and base plate unit 1024are not shown. However, it is to be understood that the unit 1024 iscomplete as shown in FIGS. 1, 4, and 9 of the drawings and has simplybeen indexed 90° with respect to the position shown in FIG. 1 of thedrawings. If, for example, the pillow type bags to be made using themachine in its converted form shown in FIGS. 23-28 of the drawings arenot to include a reclosable zipper element, the zipper drive rollers 66and 68 are not used and, as such, may be removed. However, it ispreferred that the pinch seal assembly and base plate unit 1024 remainintact with all of its components shown in FIGS. 1, 4, and 9 of thedrawings so that the machine can be converted back and forth between amachine for producing an edge fin seal bag (FIG. 1) to a machine forproducing pillow type bags (FIGS. 23-28).

As is well known in the art, each different fill tube has a particularformer which takes the planar film feed stock 22 and shapes and forms itinto the particular fill tube configuration. Thus, it is to beunderstood that the former for the fill tube 1178 is constructed toproduce a plastic tube 124 having an oval cross-section with the longdiameter extended right to left and the short diameter front to back inthe machine. Also, the particular former chosen determines which type ofoverlap or fin seal is to be produced along the midline of the pillowtype bag. In accordance with an exemplary embodiment of the presentinvention, it is preferred to use a multipurpose former which willproduce not only an overlap seal (FIG. 26) given a plastic film with oneselected width, but also will produce a midline fin seal (FIG. 27) usinga plastic film having a larger width. Thus, by using the multipurposeformer together with the fill tube 1178, one is able to produce either amidline overlap seal pillow bag or a midline fin seal (potatochip type)pillow bag.

With reference to FIG. 24 of the drawings, a fill tube backstop 1188 hasbeen added behind the fill tube 1178 to counteract the force of avertical heater platen 1190 which contacts the plastic film to produce amidline vertical seal. Without the backstop 1188, heater platen 1190 maycause the fill tube to move out of its proper vertical position andpossibly pinch the plastic film up near the former. Backstop 1188includes an elongate threaded shaft 1192 supported in a substantiallyhorizontal orientation by a bracket 1194 attached to slide rods 512 and510. The backstop 1188 is locked into position relative to the fill tube1178 by a locking nut 1196 on the threaded shaft 1192. A resilientrubber cap 1198 is added to the forward end of the shaft 1192 to preventdamage to the fill tube 1178 and the plastic film 22 wrappedtherearound.

With reference to FIGS. 24 and 25 of the drawings, when it is desired toproduce a pillow type bag having a midline overlap seal (FIG. 26) or amidline fin seal (FIG. 27) wherein the fin seal is laid flat up againstthe side of the fill tube rather than extending outwardly from the filltube (FIG. 28), it is necessary to replace the vertical heater platens88 and 90 of FIGS. 1-3 of the drawings with the single heater platen1190 which is reciprocated directly toward and away from the front faceof the fill tube 1178. In accordance with the exemplary embodiment shownin FIGS. 24 and 25 of the drawings, this single reciprocating heaterplaten 1190 is part of a vertical or longitudinal seal producing unit1200. Vertically oriented heater platen 1190 is positioned along themidline of the front of the fill tube 1178 and spaced a short distancetherefrom to provide for the edges 42 and 44 of the plastic film 22 tobe located between the heater platen 1190 and the fill tube 1178. Theheater platen 1190 has a convex edge 1202 which is reciprocated into andout of contact with the outer surface of the edge 44 of plastic film 22.The heater platen 1190 seals the edges 42 and 44 together to form thebag precursor or flexible tube 124. Heat shields may be added adjacentthe heater platen 1190 to shield the remainder of the plastic film 22and the fill tube 1178 from the heat given off by heater platen 1190.Heater platen 1190 includes one or more heater elements 1204 extendingaxially along the length of the heater platen. Heater platen 1190 byitself may have an identical construction to the heater platen 88 shownin FIGS. 1-3 of the drawings.

Vertical sealing unit 1200 also includes an elongate stainless steelconduit 1206 having a plurality of small openings 1208 and closed ends1210 and 1212 to provide for the release of pressurized air in the areaof the forward edge 1202 of heater platen 1190 to cool the verticalmidline seal formed by the heater platen. Conduit 1206 is connected toan elongate air hose 1214 which is itself connected via quickdisconnects and a solenoid valve to a source of pressurized air. Thesolenoid valve controls the timed release of the pressurized air throughoutlets 1208 in conjunction with the end of the formation of thevertical seal by heater platen 1190 during the bag forming cycle. Heaterplaten 1190 is reciprocated toward and away from the edges 42 and 44 ofthe plastic film 22 by air cylinder unit 1216 attached to a verticalsupport 1218. Cylinder unit 1216 includes a drive shaft having itsforward end connected to a vertical plate 1220. Heater platen 1190 isoperatively connected to the plate 1220 by a pair of spring biasingsupports 1222 and 1224 themselves attached to a vertical plate 1226fixed to the back of plate 1220. Each of the supports 1222 and 1224includes a spring 1228 and 1230 and an internal shaft 1232 and 1234received in respective friction-reducing bearings or bushings. Thesprings bias the heater platen 1190 forwardly of the plate 1220 butallow the heater platen to move toward the plate 1220 upon contact ofthe forward edge 1202 of heater platen 1190 with the film edges 42 and44 and the forward surface of fill tube 1178. Springs 1228 and 1230 areselected to provide the desired contact force between the forwardsurface 1202 of heater platen 1190 and the plastic film edges 42 and 44to provide for a good airtight seal while, at the same time, not harmingthe plastic film. If necessary, a resilient pad can be added to theforward surface of fill tube 1178 directly opposite heater platen 1190to further reduce the possibility of damage to the plastic film 22. Sucha resilient pad may be covered with friction-reducing tape to provide asmooth passage of the plastic film thereover. Vertical seal unit 120 isoperated by computer control system 120 in the same fashion as heaterplatens 88 and 90.

Although fill tubes 12 and 1178 of FIGS. 1 and 23 have ovalcross-sections, it is contemplated that other fill tubes havingcircular, rectangular, or larger or smaller oval cross-sections may beused to produce different sizes and styles of bags. Also, it iscontemplated that right and left whiskers can be added to the base offill tube 1178 to tension the plastic tube 124 prior to formation of thehorizontal seals by pinch seal assembly 130.

As schematically depicted in FIGS. 26-28 of the drawings, threedifferent types or styles of pillow bags may be produced. The first isthe midline overlap seal shown in FIG. 26. The second is a midline finseal which is laid flat up against the fill tube 1178 shown in FIG. 27.The third is a midline fin seal which protrudes outwardly from the filltube as shown in FIG. 28. The midline overlap seal and the midline finseal with the fin lying flat up against the fill tube are produced usingthe heater platen 1190. The midline fin seal which protrudes outwardlyfrom the fill tube 1178 is produced using vertical heater platens 88 and90 which reciprocate toward and away from one another to seal the edges42 and 44 of the plastic film 22 together therebetween. The convexworking surfaces of the heater platens 88, 90 and 1190 may be coveredwith a friction-reducing synthetic resin polymer tape or material.

In accordance with another embodiment of the present invention, avertical form, fill and seal machine for producing edge fin seal bags(FIG. 1) is constructed in accordance with FIGS. 1-22 of the drawings.

In accordance with another exemplary embodiment of the presentinvention, a vertical form, fill and seal machine for producing pillowtype bags is constructed in accordance with FIGS. 23-28 of the drawings.

The indexable pinch seal assembly and base plate unit 1024 not onlyprovides versatility but also allows for a compact side-to-sideconstruction of the machine 10. If the pinch seal assembly 130 was to berotatable about a central axis rather than indexable, the machine wouldhave to be much wider than is presently shown. In accordance with oneexample of the present invention, the base plate 1000 has outerdimensions of 37.75 inches by 37.75 inches and central opening 1004 hasdimensions of 31 inches by 21 inches.

The only tool necessary to loosen drawer front 1020 from the machine 10is a half-inch open end, box end, or socket wrench for loosening thethreaded fasteners 1066. It is also contemplated that the threadedfasteners 1066 may be replaced with wingtip bolts, or handles havingthreaded shafts to further facilitate and ease the operation ofseparating the drawer front 1020 from the frame members 1136 and 1142 toallow the pinch seal and base plate unit 1024 to be slid forwardly outof the machine. Similarly, the four corner bolts 1006 holding the baseplate 1000 to the drawer bottom 1002 may be replaced with wingtip boltsor handles having threaded shafts for facilitating the removal thereofto allow for indexing of the unit 1024. Likewise, the threaded fasteners1098 of pull belt unit 1074 may be replaced with wingtip bolts orhandles having threaded shafts to facilitate the loosening andtightening of the fasteners 1098.

Thus, it will be appreciated that, as a result of the present invention,a highly effective, improved, vertical form, fill and seal machine andmethod for producing product-filled bags is provided by which theprincipal objective, among others, is completely fulfilled. It iscontemplated, and will be apparent to those skilled in the art from thepreceding description and accompanying drawings, that modificationsand/or changes may be made in the illustrated embodiments withoutdeparture from the present invention. For example, the vertical form,fill and seal machine of the present invention may be used to produceproduct-filled bags which do not include a reclosable zipper. Zipper capstrip 52 could be replaced by either a non-zippered cap strip, a capstrip including a tear strip, or a cap strip including a reclosableelement other than a zipper. Accordingly, it is expressly intended thatthe foregoing description and accompanying drawings are illustrative ofpreferred embodiments only and not limiting.

What is claimed is:
 1. A convertible vertical form, fill and sealapparatus of the type that operates in conjunction with a product supplyapparatus providing product in discrete quantities and that forms acontinuous, heat sealable plastic film and zipper strip into separateproduct-filled, reclosable, sealed, pillow style or edge fin seal bagscomprising:a first controlled release festooner arrangement for storingand supplying a continuous plastic film; a second controlled releasefestooner arrangement for storing and supplying a continuous, plastic,zippered cap strip; a generally vertical fill tube assembly including avertical fill tube downstream of the first and second storing andsupplying festooner arrangements for the continuous film and zipperedcap strip and around which the continuous film is formed and wrapped;feeding means for feeding the zippered cap strip and plastic film alongthe length of the vertical fill tube in bag length increments with edgesof the plastic film in overlapping relationship with edges of thezippered cap strip; vertical sealing means for sealing the edges of theplastic film to the edges of the zippered cap strip to form a length offlexible, plastic tube; a pinch seal assembly downstream of the verticalfill tube for forming first and second horizontal seals across theflexible, plastic tube and for severing the plastic tube, the firsthorizontal seal defining a downstream edge of a bag about to be filledwith product and the second horizontal seal defining an upstream edge ofa bag which has already received product, said pinch seal assembly beingmounted on a rectangular base plate having a central opening for passageof said bags therethrough; and said base plate being attached to arectangular drawer bottom having a central opening for accommodatingpassage of said bags therethrough and being supported on respectivedrawer slides allowing said drawer bottom, base plate and pinch sealassembly to be drawn forwardly out of the apparatus for at least one ofservicing, maintenance, and indexing of the pinch seal assembly and baseplate through 90°.
 2. Apparatus as recited in claim 1 further comprisinga bag squeezer unit downstream of said pinch seal assembly havingopposing squeeze elements for squeezing the excess air from theproduct-filled, flexible, plastic tube prior to formation of said secondhorizontal seal and for sequentially releasing each completed,reclosable, product-filled, sealed bag following formation of the secondhorizontal seal and severing of the bag from the flexible tube. 3.Apparatus as recited in claim 2 wherein said squeeze elements compriseremovable squeeze plates mounted to respective reciprocating cantilevermeans for selectively moving said squeeze plates toward one another tosqueeze the product-filled plastic tube therebetween.
 4. Apparatus asrecited in claim 3 wherein said cantilever means are reciprocated by asingle crank rotary actuator assembly.
 5. Apparatus as recited in claim2 wherein said pinch seal assembly and said squeezer unit are eachindependent of one another and selectively actuated during bagformation.
 6. Apparatus as recited in claim 1 further comprisingtensioning means for horizontally elongating the plastic tube transverseto its length prior to formation of said horizontal seals.
 7. Apparatusas recited in claim 1 further comprising an optical sensor locatedupstream of said vertical fill tube for sensing registration marks onsaid plastic film.
 8. Apparatus as recited in claim 1 wherein saidfeeding means includes a plastic film drive roll, a pair of pull belts,and a pair of zippered cap strip drive rollers.
 9. A convertiblevertical, form, fill and seal apparatus of the type that operates inconjunction with a product supply apparatus providing product indiscrete quantities and that forms a continuous, heat sealable, plasticfilm into separate product-filled sealed pillow type or edge fin sealbags comprising:first means for storing and supplying a continuous,plastic film; second means for storing and supplying a continuous,plastic cap strip; a generally vertical fill tube assembly including avertical fill tube downstream of said first means for storing andsupplying the continuous plastic film, said vertical fill tube being atube of oval horizontal cross-section and means for forming said plasticfilm around said vertical fill tube; feeding means including a plasticfilm drive roll, a pair of pull belts, and a pair of cap strip driverollers for feeding the cap strip and the plastic film along the lengthof said vertical fill tube in bag length increments; vertical sealingmeans for sealing the edges of the plastic film to the edges of the capstrip to form a length of flexible, plastic tube; each of said pair ofpull belts being mounted on a respective side of the vertical fill tubeand biased against the plastic film and said vertical fill tube;horizontal sealing and severing means downstream of said vertical filltube for severing the plastic tube and forming first and secondhorizontal seals across the plastic tube, the first horizontal sealdefining a downstream edge of a bag about to be filled with product andthe second horizontal seal defining an upstream edge of a bag which hasalready received product; tensioning means for horizontally elongatingthe plastic tube transverse to its length prior to severing andformation of said first and second horizontal seals; and, drawer meansfor supporting said horizontal sealing and severing means and includinga central opening for accommodating passage of said bags therethroughand providing for horizontal movement of said horizontal sealing andsevering means for at least one of servicing, adjustment, replacement,and indexing of horizontal sealing and severing means through 90°. 10.Apparatus as recited in claim 9 further comprising squeezing means forremoving excess air from the product-filled plastic tube prior toformation of said horizontal seals.
 11. Apparatus as recited in claim 10wherein said squeezing means and said horizontal sealing and severingmeans include separate, independent reciprocation means and are mountedfor separate and independent reciprocation toward and away from saidplastic tube.
 12. Apparatus as recited in claim 10 wherein saidsqueezing means includes a pair of opposing removable squeeze platesoperatively connected to a rotary actuator assembly for selectivereciprocation toward and away from said plastic tube.
 13. Apparatus asrecited in claim 9 wherein said tensioning means includes said cap stripdrive rollers and an opposing rod extending downwardly from saidvertical fill tube.
 14. Apparatus as recited in claim 10 wherein saidtensioning means further includes bag grabber means comprising a pair ofopposing air cylinder units located downstream of said vertical filltube for selectively clamping said plastic tube therebetween.
 15. Aconvertible vertical, form, fill and seal apparatus of the type thatoperates in conjunction with a product supply apparatus providingproduct in discrete quantities and that forms a continuous, heatsealable, plastic film into separate, product-filled, sealed, pillowstyle or edge fin seal bags comprising:a controlled release festoonerarrangement for storing and supplying a continuous plastic film; agenerally vertical fill tube assembly including a vertical fill tubedownstream of the festooner arrangement for the continuous film andaround which the continuous film is wrapped and formed; feeding meansfor feeding the plastic film along the length of the vertical fill tubein bag length increments with edges of the plastic film adjacent oneanother; vertical sealing means for sealing the edges of the plasticfilm to one another to form a length of flexible, plastic tube; a pinchseal assembly downstream of the vertical fill tube for forming first andsecond horizontal seals across the flexible, plastic tube and forsevering the plastic tube, the first horizontal seal defining adownstream edge of a bag about to be filled with product and the secondhorizontal seal defining an upstream edge of a bag which has alreadyreceived product; said pinch seal assembly being mounted on arectangular base plate having a central opening for passage of said bagstherethrough, said base plate being attached to a rectangular drawerbottom having a central opening for accommodating passage of said bagstherethrough and being supported on respective drawer slides allowingsaid drawer bottom, base plate and pinch seal assembly to be drawnforwardly out of the apparatus for at least one of servicing,maintenance, and indexing of the pinch seal assembly and base platethrough 90°.
 16. Apparatus as recited in claim 15 further comprisingtensioning means for horizontally elongating the plastic tube transverseto its length prior to formation of said horizontal seals.
 17. Apparatusas recited in claim 15 further comprising a bag squeezer unit downstreamof said pinch seal assembly having opposing squeeze elements forsqueezing the excess air from the product-filled, flexible, plastic tubeprior to formation of said second horizontal seal and for sequentiallyreleasing each completed, product-filled, sealed bag following formationof the second horizontal seal and severing of the bag from the flexibletube.
 18. A convertible vertical, form, fill and seal apparatus of thetype that operates in conjunction with a product supply apparatusproviding product in discrete quantities and that forms a continuous,heat sealable, plastic film into separate, product-filled, sealed pillowtype or edge fin seal bags comprising:means for storing and supplying acontinuous plastic film; a generally vertical fill tube assemblyincluding a vertical fill tube downstream of said means for storing andsupplying a continuous plastic film and means for forming said plasticfilm around said vertical fill tube; feeding means including a plasticfilm drive roll and a pair of pull belts for feeding the plastic filmalong the length of said vertical fill tube in bag length increments;vertical sealing means for sealing the edges of the plastic film to oneanother to form a length of flexible, plastic tube; each of said pair ofpull belts being mounted on a respective side of the vertical fill tubeand biased against the plastic film and said vertical fill tube;horizontal sealing and severing means downstream of said vertical filltube for severing the plastic tube and forming first and secondhorizontal seals across the plastic tube, the first horizontal sealdefining a downstream edge of a bag about to be filled with product andthe second horizontal seal defining an upstream edge of a bag which hasalready received product; tensioning means for horizontally elongatingthe plastic tube transverse to its length prior to severing andformation of said first and second horizontal seals; and, drawer meansfor supporting said horizontal sealing and severing means and includinga central opening for accommodating passage of said bags therethroughand providing for horizontal movement of said horizontal sealing andsevering means for at least one of servicing, adjustment, replacement,and indexing of said horizontal sealing and severing means through 90°.19. Apparatus as recited in claim 18 further comprising squeezing meansfor removing excess air from the product-filled, plastic tube prior toformation of said horizontal seals.
 20. A convertible vertical, form,fill and seal apparatus of the type that operates in conjunction with aproduct supply apparatus providing product in discrete quantities andthat forms a continuous, heat sealable, plastic film into separate,product-filled, sealed, pillow type or edge fin seal bagscomprising:means for storing and supplying the continuous plastic film;a generally vertical fill tube assembly including a vertical fill tubedownstream of the means for storing and supplying the continuous filmand around which the continuous film is wrapped and formed; feedingmeans for feeding the plastic film along the length of the vertical filltube in bag length increments with edges of the continuous film inoverlapping relationship with one another; vertical sealing means forsealing the edges of the continuous film together to form a flexible,plastic tube; horizontal sealing and severing means downstream of thevertical fill tube for forming upper and lower horizontal seals acrossthe flexible, plastic tube and for severing the plastic tube; and,drawer means for supporting said horizontal sealing and severing meansand including a central opening for accommodating passage of said bagstherethrough and providing for horizontal movement of said horizontalsealing and severing means for at least one of servicing, adjustment,replacement, and indexing of said horizontal sealing and severing meansthrough 90°.
 21. A convertible vertical, form, fill and seal apparatusof the type that operates in conjunction with a product supply apparatusproviding product in discrete quantities and that forms a continuous,heat sealable, plastic film into separate, product-filled, sealed,pillow type or edge fin seal bags comprising:means for storing andsupplying a continuous, plastic film; a generally vertical fill tubeassembly including a vertical fill tube downstream of said means forstoring and supplying the plastic film, said vertical fill tube being atube of oval horizontal cross-section and means for forming said plasticfilm around said vertical fill tube with edges of the plastic filmmeeting at one end of the minor diameter of said tube; feeding meansincluding a plastic film drive roll and a pair of pull belts for feedingthe plastic film along the length of said vertical fill tube in baglength increments; vertical sealing means for sealing the edges of theplastic film to one another to form a length of flexible, plastic tube;each of said pair of pull belts being mounted on a respective side ofthe vertical fill tube and biased against the plastic film and saidvertical fill tube; horizontal sealing and severing means downstream ofsaid vertical fill tube for severing the plastic tube and forming firstand second horizontal seals across the plastic tube, the firsthorizontal seal defining a downstream edge of a bag about to be filledwith product and the second horizontal seal defining an upstream edge ofa bag which has already received product; and, drawer means forsupporting said horizontal sealing and severing means and including acentral opening for accommodating passage of said bags therethrough andproviding for horizontal movement of said horizontal sealing andsevering means for at least one of servicing, adjustment, replacement,and indexing of said horizontal sealing and severing means through 90°.22. A convertible vertical, form, fill and seal apparatus of the typethat operates in conjunction with a product supply apparatus providingproduct in discrete quantities and that forms one or both of acontinuous, heat sealable, plastic film and zipper strip into separate,product-filled, reclosable or non-reclosable, sealed, pillow style oredge fin seal bags comprising:a first controlled release festoonerarrangement for storing and supplying a continuous, plastic film; asecond controlled release festooner arrangement for storing andsupplying a continuous, plastic, zippered cap strip; a generallyvertical fill tube assembly including a vertical fill tube downstream ofthe first and second storing and supplying festooner arrangements forthe continuous film and zippered cap strip and around which thecontinuous film is wrapped and formed; feeding means for feeding atleast one of the zippered cap strip and plastic film along the length ofthe vertical fill tube in bag length increments; vertical sealing meansfor sealing at least one of the edges of the plastic film to the edgesof the zippered cap strip and the edges of the plastic film to oneanother to form a length of flexible, plastic tube; a pinch sealassembly downstream of the vertical fill tube for forming first andsecond horizontal seals across the flexible, plastic tube and forsevering the plastic tube, the first horizontal seal defining adownstream edge of a bag about to be filled with product and the secondhorizontal seal defining an upstream edge of a bag which has alreadyreceived product; and, said pinch seal assembly being mounted on arectangular base plate having a central opening for passage of said bagstherethrough, said base plate being attached to a rectangular drawerbottom having a central opening for accommodating passage of said bagstherethrough and being supported on respective drawer slides allowingsaid drawer bottom, base plate and pinch seal assembly to be drawnforwardly out of the apparatus for at least one of servicing,maintenance, and indexing of the pinch seal assembly and base platethrough 90°.
 23. Apparatus as recited in claim 22 further comprising abag squeezer unit downstream of said pinch seal assembly having opposingsqueeze elements for squeezing the excess air from the product-filled,flexible, plastic tube prior to formation of said second horizontal sealand for sequentially releasing each completed, reclosable,product-filled, sealed bag following formation of the second horizontalseal and severing of the bag from the flexible tube.
 24. A convertiblevertical, form, fill and seal apparatus of the type that operates inconjunction with a product supply apparatus providing product indiscrete quantities and that forms a continuous, heat sealable, plasticfilm into separate, product-filled, sealed, pillow style or edge finseal bags comprising:means for storing and supplying the continuousplastic film; a generally vertical fill tube assembly including avertical fill tube downstream of the means for storing and supplying thecontinuous film and around which the continuous film is wrapped andformed; feeding means for feeding the continuous plastic film along thelength of the vertical fill tube in bag length increments with edges ofthe continuous film in at least one of overlapping relationship andabutting relationship; vertical sealing means for sealing the edges ofthe continuous film to one another to form a flexible, plastic tube;horizontal sealing and severing means downstream of the vertical filltube for forming upper and lower horizontal seals across the flexible,plastic tube and for severing the plastic tube; and, drawer means forsupporting said horizontal sealing and severing means and including acentral opening for accommodating passage of said bags therethrough andproviding for horizontal movement of said horizontal sealing andsevering means for at least one of servicing, adjustment, replacement,and indexing of said horizontal sealing and severing means through 90°.25. In a vertical, form, fill and seal apparatus including a verticalfill tube, vertical sealing means, and horizontal sealing and severingmeans and of the type that forms a continuous, heat sealable, plasticfilm and a continuous, plastic, zippered cap strip into a flexible tube,a three-sided, partially formed, product-filled bag and then into afour-sided, separate, reclosable, product-filled, sealed bag, theimprovement comprising:drawer means for supporting said horizontalsealing and severing means and including a central opening foraccommodating passage of said bags therethrough and providing forhorizontal movement of said horizontal sealing and severing means for atleast one of servicing, adjustment, replacement, and indexing of saidhorizontal sealing and severing means through 90°.
 26. In a vertical,form, fill and seal apparatus including a vertical fill tube, verticalsealing means, and a pinch seal assembly and of the type that forms acontinuous, heat sealable, plastic film into a flexible tube and theninto separate, sealed bags, the improvement comprising:said pinch sealassembly being mounted on a rectangular base plate having a centralopening for passage of said bags therethrough, said base plate beingattached to a rectangular drawer bottom having a central opening foraccommodating passage of said bags therethrough and being supported onrespective drawer slides allowing said drawer bottom, base plate andpinch seal assembly to be drawn forwardly out of the apparatus for atleast one of servicing, maintenance, and indexing of the pinch sealassembly and base plate through 90°.
 27. In a vertical, form, fill andseal apparatus including a vertical fill tube, vertical sealing means,and horizontal sealing and severing means and of the type that forms acontinuous, heat sealable, plastic film and a continuous, plastic, capstrip into a flexible tube, a three-sided, partially formed,product-filled bag and then into a four-sided, separate, product-filled,sealed bag, the improvement comprising:drawer means for supporting saidhorizontal sealing and severing means and including a central openingfor accommodating passage of said bags therethrough and providing forhorizontal movement of said horizontal sealing and severing means for atleast one of servicing, adjustment, replacement, and indexing of saidhorizontal sealing and severing means through 90°.
 28. In a convertiblevertical, form, fill and seal apparatus including a vertical fill tube,vertical sealing means, and a pinch seal assembly and of the type thatforms a continuous, heat sealable, plastic film into a flexible tube andthen into separate, sealed, pillow type or edge fin seal bags, theimprovement comprising:said pinch seal assembly being mounted on arectangular base plate having a central opening for passage of said bagstherethrough, said base plate being attached to a rectangular drawerbottom having a central opening for accommodating passage of said bagstherethrough and being supported on respective drawer slides allowingsaid drawer bottom, base plate and pinch seal assembly to be drawnforwardly out of the apparatus for at least one of servicing,maintenance, and indexing of the pinch seal assembly and base platethrough 90°.
 29. In a convertible vertical, form, fill and sealapparatus including a vertical fill tube, vertical sealing means, andhorizontal sealing and severing means and of the type that forms atleast one of a continuous, heat sealable, plastic film and a continuous,plastic, zippered cap strip into a flexible tube, a three-sided,partially formed, product-filled bag and then into a four-sided,separate, reclosable or non-reclosable, product-filled, sealed pillowtype or edge fin seal bag, the improvement comprising:drawer means forsupporting said horizontal sealing and severing means and including acentral opening for accommodating passage of said bags therethrough andproviding for horizontal movement of said horizontal sealing andsevering means for at least one of servicing, adjustment, replacement,and indexing of said horizontal sealing and severing means through 90°.30. A method of converting a convertible, vertical, form, fill and sealmachine from a machine for making reclosable, edge fin seal,product-filled bags to a machine for making midline overlap seal, pillowtype nonreclosable bags comprising the steps of:changing a bag formingfilm stock roll in a back of the machine, adjusting a film path lengthand machine controls for a new bag type, size, product and the like,changing a former and fill tube, using slidable drawer means to index apinch seal assembly 90° so that respective pinch seal clamping jaws arelocated in front and behind a plastic tube rather than to right and leftsides thereof.
 31. The method as recited in claim 30 wherein saidindexing of the pinch seal assembly is facilitated by having the entireassembly mounted on a base plate which is itself mounted on a drawermechanism which allows the pinch seal assembly to be pulled forwardlyout of the machine, lifted from the drawer, indexed 90°, set back intothe drawer and then pushed back into the machine.
 32. A method of movinga pinch seal assembly and base plate unit mounted on a drawer bottom ofa slidable drawer means including a drawer front attached to the drawerbottom in a vertical, form, fill and seal machine from a bag productionposition in the machine to a forward servicing or indexing position, themachine having a supply of plastic film and zipper strip, means forfeeding the plastic film and zipper strip through the machine, a machinecontrol system, a machine frame supporting machine components, anelectrical quick disconnect in an electrical cable to the pinch sealassembly, a hinged whisker having a movable locking collar, the pinchseal assembly including rear components of a disc, belt and actuator,comprising the steps of:clearing the plastic film and zipper strip fromthe area of the pinch seal assembly, shutting off power to the machinecontrol system, loosening threaded fasteners holding the drawer front tothe machine frame, uncoupling the electrical quick disconnect andstowing the electrical cable up and out of the way, raising the lockingcollar up off of a hinge in the whisker to allow a lower end of thewhisker to swing out of the way of the rear pinch seal assemblycomponents including the disc, belt and actuator, and then pulling thedrawer front forwardly which pulls the base plate drawer bottom, andpinch seal assembly forwardly a desired distance.
 33. The method asrecited in claim 32 further comprising the steps of indexing the pinchseal assembly and base plate unit 90° by removing four corner bolts tofree the base plate from the drawer bottom, lifting the pinch sealassembly and base plate unit sufficiently to clear the drawer front,rotating the unit 90° clockwise, placing the unit back on the drawerbottom, and reattaching the base plate to the drawer bottom using thefour bolts.
 34. The method as recited in claim 33 further comprising thesteps of placing the pinch seal assembly and base plate unit back in anoperative pillow type bag production position by pushing the drawerfront back toward the machine until the drawer front contacts themachine frame, inserting the bolts, reattaching the electrical cable tothe box, sliding the locking collar over the whisker hinge, and turningthe power back on to the machine control system.
 35. A pinch sealassembly, base plate and drawer unit for a vertical, form, fill and sealmachine comprising:a pinch seal assembly for forming first and secondhorizontal seals across a flexible plastic tube and for severing theplastic tube between the said horizontal seals; a rectangular base platesupporting said pinch seal assembly and including a central opening forpassage of said plastic tube therethrough; a rectangular drawer bottomsupporting said base plate and including a central opening for passageof said plastic tube therethrough; and, drawer slides supporting saiddrawer bottom and allowing said drawer bottom, base plate, and pinchseal assembly to be simultaneously moved; whereby said drawer unitindexes said pinch seal assembly 90° in order to form pillow and finseal type bags.
 36. The unit as recited in claim 35 wherein said pinchseal assembly includes quick disconnect means for at least one ofelectrical, pressurized air and rotary drive elements.